So from where all will the fluid come out? I have not ripped apart a t-5 recently, but from my other trannys, I bet the tail shaft, the shifter hole and from a vent? But no pieces should fall out.
Aside from the areas you just named you should be fine. No mechanical parts will fall out. Everything is pressed our held in place. Once the fluid is drained flip it over any way you like to get it cleaned. I use brake cleaner to cut through all the grime myself.
I have to be a wise crack. If you flip the transmission over, make sure it is still not attached to the car. Leaking fluid and loose tranny parts will be the least of your worries. Keep the shiny side up!