Does she have to sign the payment agreement for it to be enforceable?

I've always gotten a signed "authorization to release loan info" from the owner on record. 

So as a result of my “asset protection” procedures, the end result was that instead of being sued personally and having to spend the time, money and emotional stress of both defending my self AND suing the insurance companies and condo association, the plaintiffs accepted an ASSIGNMENT of proceeds and signed a form releasing me and my LLC from liability in exchange for the right to go after the insurance companies themselves. 

I never heard back, but all 7 clients apart from the “whale” client re-signed with me.

Offer accepted, "My I have an email to send you a purchase and sale agreement via Adobe Sign" Offer rejected, put in the follow up bin.

And it was a pain because guests kept signing out to use their own.So we just cancelled all services and we state on the listing that guests need to provide their logins for apps.I know we'll have issues with older guests.

I signed up for a 7 day free trial to try out the tools, but I forgot to cancel on time.

Will he co-sign on loans from banks or private lenders, or will he just say, call 15 banks?

I would also note your mention of not wanting liability, but offering to "co-sign".

Lenders and appraisers may see this as a sign of a room-by-room rental setup.