I bought the east hallway upgrade for the manor and I don't know how to invite more people, help
also, if i download the new update will i have the same saves
On PC/Mac, yes.
On Android make sure you don't uninstall the previous version.
Of if you do, make a backup, more info in the discord server.
As for the east hallway.
You can invite Jessica's friends after you've seen their second event.
And you have the chance to invite two (or three) more people related to the FEY storyline if you progress far enough.