So it sounds like you want to deposit at two schools, defer your attendance at one while you try the other, and then come back to the first if the second doesn’t work out well
First, it is against the rules to double deposit.
Second, in my limited experience, if you request a deferral, they want to know what you plan to do during that deferral before granting it. Trying out another school would not be a good answer, and they probably wouldn’t grant that deferral.
The best way forward is to pick the school you like best. If it doesn’t work out, apply to transfer.