Sounds as though the intro went nicely. Remember that the relationships change continually and that there will be some spats and some nasty ones at that. If they all three get along somewhat now, I suspect it will run just fine from this point. There will probably always be the bossy one, the shy one, etc. etc. but that is how it is in the cat world. You are lucky they are all ok with each other. I guess that is the word OK. Seldom is it perfect.

Three times everything, including litter duty!

Ugh!