The 'conforming loan' box is highly restrictive for investors. 

Typically better to get conforming mortgage (Fannie Mae guaranteed) outside of an LLC.

But let me see if I can give you another different piece of advice when it comes to these guys:  On the one hand, Boston EXPECTS Zoning issues (setbacks, non-conforming uses, height variances,  etc.) because the land is so dense and land use is so tough.  

I conformed, wish I hadn't.I say that because I'm rather a target on here, my doings, but you get some folks with insurance companies and banking assets that can be misused to obtain personal information, I've been harassed with under the radar remarks referring to my other assets, where I bank and other personal aspects made public.

If he appraises the property and says that the extra living unit is a non-conforming use via the city zoning, you will have much more problems.

Are non-conforming bedrooms still technically a bedroom and can it be advertised as a bedroom?

I have the credit, I have the liquid capital, I have knowledge where I am conformable enough to understand make an educated decision.

as you prob know - 2018 conforming loan limits  increasing in King County are higher ...

I am looking at a MHP that recently learned via a survey that if any of the homes are replaced, all the pads on that road must be conforming.

The lender will give you the option to pay the contractor directly but this is going to be a headache in itself as they have to conform to the lender's payment request system and timing.