A good glue you can use for soft plastic which is a flexible material is Gorilla Glue.
No, not a good idea. Best to get a replacement.
if it is a plastic model kit you can use super glue, but not wood glue.
You have to use glue of course and you need someone to hold it together while you glue it
Use soap
no
You should use a special type of glue called acrylic cement or solvent cement for bonding acrylic plastic.
ALL plastics have their own particular glue or solvent - USE it rather than any other.
No, it will not glue it, just dry up and become flaky. You must use a proper glue for each plastic. - Yellow glue is only for ABS.
Super glue
No, try an apoxy, super glue, or zap a gap. N
Super glue is best for this