RoseFlower

Not sure a bubble bum inflatable booster would be appropriate for a 3 year old.  Try Cortrans or Cruise Control Transportation.  They have likely dealt with car seat issues before.

You might want to get inflatable car seats. The ride from MCO to the port is about an hour, possibly more with traffic. 

I'm not sure where your hotel is so this may be completely irrelevant information and if so I apologize. But for a few comparable items, I just went through the same thing. We're staying at a hotel in Cocoa Beach and needed transportation from MCO to the hotel, then after the cruise from Port Canaveral back to MCO. From hotel to Port on the morning of the cruise we're good.
GoPort.com offered us (2 adults / 2 children) from MCO to Port Canaveral at $120. That was MCO to Port only, however, they wouldn't do anything MCO to a hotel. 
Cortans was $30 per person each way, so $120, same as GoPort.
Cocoa Beach Shuttle offered us MCO to our hotel for $85 flat fee, and then from Port to MCO at the end of the cruise for $89. 
We found Cocoa Beach Shuttle to be the cheapest and easiest. They will send a van right to MCO and we may share a ride we may not, but we know we're going to get there and they offered services well past 5:30 (really late did have an upcharge to be transparent). 
We tried to find estimates with Uber/Lyft but that can be unreliable given surge/time/etc. but found that they wouldn't necessarily beat $85 in most cases, or so we thought. 
Hope that helps!

Demand and capacity is related to pricing and vice versa.  Short of a proper sine wave cruise pricing traditionally goes through a series of peaks and troughs of unequal amplitude. 
In summary:
Prior to the shutdown ships sailed full.  Capacity was at or above 100% most of the time.  The only difference when viewed across 12 months of cruising was in the rates paid and how many guests on board were the result of last minute tactics to fill the ship.   
If you are only interested in how full the ships were (capacity) it's pretty simple.  They were always full prior to the shutdown, during the initial restart well under 50% and in the final phases of the restart (as in now) at or above full capacity, at least in the US but not in Europe.   Europe remains soft averaging 70% capacity so it does matter what region you are looking to sail.
 
The long story:
Cruise lines are constantly looking for ways to increase prices which can lower demand.  In the near term (2022-2024) I think we'll see cruise lines getting very narrow in the data and trend analysis as they try to test the market with higher rates and minimize the traditional troughs during the annual pricing trend saga.  I also think their efforts will eventually prove fruitless and we'll see traditional pricing trends return to the industry but they are going to try to increase rates as much as they can.
Traditionally spring break is period of moderate or medium demand as evidenced by the medium price trends.  In the US summer vacation represents the traditional high or market peak.  Christmas vacation represents a secondary but briefer spike in prices approaching that of the summer peak in amplitude.  Spring break represents an upward peak relative to the months before and after but usually half the amplitude of the summer peak.  The summer is really when cruise lines make bank.  For anyone purely interested in capacity all that is meaningless.  Ships will sail full.
Despite stating they don't Royal has traditionally used many tactics to fill the ships at the last minute.  The primary method is casino comps.  A secondary method involves promos like Going, Going, Gone.  Here is where demand and capacity can deviate from each other as they fill ships at lower prices but only for targeted demographics such as casino players.   Once again, for anyone purely interested in capacity all that is meaningless.  Ships will sail full.
Prior to the shutdown ships usually sailed full (capacity 100) while the demand and pricing didn't directly correlate.  Demand from vacation guests who book years in advance is different from increased capacity created by casino comps and last minutes promos to fill the ship.  The first accounts for pre-cruise revenue while the latter represents more of a shift towards on board revenue as a source while giving away the cruise fares to earn that on board revenue (lost leader).   For anyone purely interested in capacity all that is meaningless.  Ships will sail full.

Couldn't agree more and I have no kids. The beauty of it for me is that it can appeal to so many people in so many different ways.
Kids, no kids, young, old, beach lover or not, pool lover or not, snorkeler or not, loud music lover or not, food over-indulger or not, water park enthusiast or not, spend money on a cabana or spend nothing extra... you get the idea.
We went on a B2B 3 and 4-nighter last month and the double Cococay stop was one of the reasons. It wasn't the only reason but we may do the exact same thing in October.

We have been trying to get to Coco cay since before this miserable pandemic and we are finally here on Oasis. This could not be better and cooler. I watched, we watched a million videos of this island and none of really prepared us for how freaking awesome it truly it. Kids are having a blast and there is no better value on vacations at all. We will be back here on Oasis or anthem and probably both. This splash away bay is just amazing. The dump buckets are just so much fun. This vacation was worth every penny even with a 7 month old which can be a bit challenging at times. 9 year old is having the time of his life. Just loving this! Loving this!

I agree, the MDR staff always let us know how important 10s are and on our last cruise was event mentioned that if they get all 10s they get an extra day off.  It’s really uncomfortable for us since they’ve already earned a 10  with the amazing service.  I know they really want everyone to complete the survey and Royal needs to find a better way to incentivize passengers to complete the survey, so the staff aren’t “begging” for scores. It’s a small thing, but t leaves us with a bad taste right at the end of the trip.

I just completed my Oasis of the Seas survey.  Overall, we had a great time, and my survey responses reflect it.  However, I always hesitate on one question.
'Has any cruise member requested a positive rating, and if so... who?"  I never really know how I should answer this question.  My experience over the years is that we always have at least one crew member does in fact says something like 'remember, you will be getting a survey and it is very important that you provide your feedback, but my manager considers anything less than 10, a failure".   
I never answer the survey question 'yes', because I don't really want to throw anyone under the bus... but should I? 
Do the crew members know that this question is on the survey?  If so, why do they still request a 10?
Am I doing a disservice to all, by not 'reporting' the crew member?  Anecdotally, it is almost always dining room waiters/asst waiters that even mention the surveys and comment on it.
 
What are some other thoughts on this? 

I go to place like party city and buy a bunch of those glow in the dark necklaces. Put one on bathroom door handle at night. One inside bathroom as nightlight etc. Just enough light to not wake people up.

BOOK now if its a price you are comfortable with... Prices generally will only go up.  Next cruise prices are the same (for the most part) as current prices on website. Benefit of Next Cruise is reduced deposit and On board credit.  The OBC will not make up for the fare increase 3 months from sail date. You can always reprice before final payment date if fare goes down. Use a good Travel Advisor ( MEI for example) and have peace of mind with Flight and hotel bookings!
Enjoy the cruises!