How many props will a character be able to use? There are two parts to the is question:
First, how many props can be visible/held at any time? For instance can a character dual wield two props while also carrying a shoulder pet (would a shoulder pet even be considered a prop)?
Second, can a player swap props from ability activation to ability activation? For instance, can a magic-themed character use a wand for one ability, open a book for a second ability and thrust forth a skull for a third ability?
I like to take your ideas and supersize them. This isn't criticism, it is flattery. I come with nothing but good will and a spirit of team-building. If you take what I write any other way, that is probably just because I wasn't very clear.