Easiest answer first - strollers are left outside like any other ride or show
It's been quite a long time since I did a show dining package (my first after a lengthy break is for ROL in the beginning of June
So, I am a little rusty - I do not recall if you are given a paper ticket for 4 or 4 paper tickets for a party of 4
I almost always err on the side of following the rules
If it is one piece of paper for your family - simplest scenario, you all have to enter at the same time, when you do is your decision
If 'seat in the chair' is given their own ticket to the show after dining, the rules and adherence becomes a little more interpretive and starts encroaching on your comfort zone
I follow the rules, and admittedly am annoyed by others who do not when they are clearly stated - so, if the paper says show up together - we're there together - if the paper says show up 30 minutes before showtime - it's my decision if I push the time boundaries a little - as a GROUP - however, if I am there with my group as stated 30 minutes ahead of show time - and there is half of a group, holding twice their width in a prime location - that group is playing with the patience of the Disney staff (who are taught the mantra 'please move all the way to the end of the row') and the Disney customers - yes, there are circumstances, but in general we would all like to get in one last ride before the show - please don't save seats for this reason, make the choice to separate from the rest of your group for one last drop at Tower and choose to enter later (if possible) and pick a place to meet after the show
Again - sorry, I'm a Libra - I'm all about fair and rules to me - others may be more flexible - I'm sure there are many opinions