Either agreement will need to clearly spell out the rights and obligations of the partners/members, and include terms for transfers of interests, dissolution, and selling the property, among other terms. 

Will I be able to transfer the property into an LLC with an open HELOC?

So, I am looking for a closing attorney with experience in constructing Owner Financing/Lease Options/"Subject To" deals and LLC Membership Assignments/Transfer.

If you do, the judge can undo that action citing that you were attempting to hide assets from a legitimate creditor, which falls under fraudulent transfer of assets.So, don't know if your married or if your state has the same rules, but that was something cool I learned recently from my Estate Planning attorney.Bottom line: I'd ask a Pro to be sure.

The market for single family may not crash in the intermediate term, but the assets and wealth will be transferred from mom and pops to corporations and single family syndicators.

The property being transferred in this arrangement must be owned free and clear by the seller.Opportunities"This approach lends itself well to selling properties that may be difficult to compare due to unique construction, number of bedrooms, etc."

It is often better to do a transfer on death to get the step up basis.If you want to gift it without triggering taxes you can create a multi member LLC where your mother has initially all the membership and gifting you each year up the the exclusion value, taking into consideration that the fair market value of this portion of membership will be probably 20 to 40% lower than the same portion of the full market value of the property due to its non marketability.

Reminder in MI to file a Property Transfer Affidavit (PTA) and change your insurance to new LLC name if you do change the ownership. 

Once you buy the property, you can transfer it into an LLC, but that won't affect the initial rate you get or your ability to qualify.

Because of C19 I bet banks a bit more restrictive on the transfer to LLC right now.