as a wholesaler after assigning contract to end buyer with existing mortgage and they take over, would it be reccomeded if i tell the end buyer about creative financing to another potential buyer

In my models, I have expenses (less mortgage payments) track the same number so I find the total rate of return to be relatively insensitive to this number.

$6,100 PITI + Maintenance, Cap Ex, & vacancy reserves Versus whatever similar rent would be in the area.If you're okay with this deal not being a homerun initially, but allowing you to live in an ideal location in a nice home with slightly less mortgage cost, then it may be worth it. 

Here is a list of lenders specializing in these kinds of loans:https://www.biggerpockets.com/member-blogs/2810/50272-list-o...What if the self directed Roth IRA purchases a property "Subject To" the Seller's existing mortgage? 

They are the ones who also have the mortgage office which is what a lot of the servicers use but that is an overkill and way to expensive.I also know some people have created flows withing clickup and other project management systems. 

One more question, is it possible (and lawful) to apply for the mortgage conventionally (under my name as an individual) for a more favorable rate, and then assign the asset to the LLC at a later date? 

If you walk out your front door and talk to your neighbors about finance - they will talk about the interest rate on their mortgage, their 401k and T-Bills. 

I work in the mortgage industry and the appraiser can use stick built homes of similar quality as comparable sales for modular homes.  

Trying to learn it online and apply on your own is risky.

Lenders will already have the closing docs, but your friends will need to have an attorney draft the promissory note, Deed of Trust (in TX or other Deed Theory States) or the mortgage in Lien Theory States like me home state of Florida, and other ancillary documents that go along with a loan of this type.