In larger cities this is a pretty common arrangement, especially for large apartment buildings.

I want to make arrangements so my sister can take care of the management or sales of these properties and then transfer them to my daughter when she is a legal adult. 

A fully amortized installment arrangement.

I call the contractor, let them know what the issue is, give them the tenants contact info to arrange a convenient time, they send me a quote or if an emergency call me on the spot, I authorize the repair or get more quotes and then they email me receipt and, as prearranged, I pay by credit card over phone.

The seller and I agreed that I could make a down payment for their back taxes and set up payment arrangement for the remaining balance.

But put this new arrangement into an addendum to the lease so that in case the tenant stops reimbursing you, it is a lease violation and grounds for eviction.

Maybe figure out a way to house hack your student living arrangements.  

Question is what does your broker think......wholesaling for an agent is nothing more than a net listing arrangement, run that by your broker.

If you are inflexible the arrangement will last only until the newbie saves enough to it on their own. 

Definitely don't want to do anything resembling fraud, but I thought that the seller financing deal didn't come with a lien, which makes no sense when you think about it (how could he protect himself then?).