A relative may be sufficiently motivated to work with you.It may be that a formal Conservatorship has been established.

In the case of cash offers, proof of funds may be sufficient for the purposes of making an offer.  

My question is will this be sufficient protection from all personal assets?

This is known as the self-sufficiency rule.

And, above a certain rental rate, potential tenants are what we call transitional, they have sufficient income to buy a property so they are only renting because of a specific issue that will likely resolve over time.

This is known as the self-sufficiency rule.

Verify that property passes the Self Sufficiency test *this is a rule for multi family properties purchased using FHA.

In the states where I work, square footage by an appraiser would not be a sufficient out of a contract.

If you will not - or cannot - bring capital into a deal, then you need to be able to provide sufficient value that others will ... and will allow you to invest it on their behalf.

@Wendy Lovejoy I had real estate agents that wanted me to spend all my cash on 1 house, refused to place low offers that produce sufficient cash flow, argued with me because I wanted to see multiple houses "the funnal" but not make an offers.