I am looking at charging 25% to do this as a stake holder with my partner.

My understanding is credit cards can not put a lien on a holders real estate, credit card payoff amounts are not required by title agents like mortgage and taxes. 

Remember, a voucher holder is required to use 30% of their income for housing, regardless of the rent amount.

It isn't a deal killer, but in this situation I'd talk to the holder of the Land Contract and see if he's on board.

I’m hoping to get some advice on this matter so that I can avoid blindness to potential risks and to be able to ask the proper questions (of him and the current note holder).

Of course the money is not liquid, and I became a lien holder without even having my own house (I rent now) but I did this out of 1) good heart and 2) get started on RE without risking too much.

The grantor is who creates trust, the beneficiary is the holders of the trust and the trustee is the managers.  

I would also ask your attorney or title company if there is a statute of limitations for a lien holder to file suit. 

If yes to the latter, does that imply that a lien holder can foreclose early on the home if the deed is purchased (before the usual 2 year period)?

A lot of long term holders just don't care what the market does.