(wisconsin)How can I best position myself in this deal where the lender is comfortable and we have a solid prefab, but also workable to where I can keep my sale price competitive and build costs down.This lot is within spitting distance of the lake.

With down payments, improvements, commissions, title work, holding costs etc....

The catch was that it would cost me $7k.

You can also assess a dollar amount that you value the cost of these requests to be, and ask for these as a discount from the purchase price or a concession to you for closing costs. 

I think it just benefits current owners. our replacement cost variability just went up a lot for the next 4 years.

You could also get a line of credit for about $150k (you should be able to borrow 75% of the value.)The reason I suggest this is…1) you save $40-$60k in selling costs. 2) you have a lower blended interest rate (2/3rds at 3.25% and 1/3rd at 7 or 8% instead of the whole $500k at 7 or 8%) saving you another $1k/mo in interest. 3) you only pay interest on that $150k when you actually use it, not from day 1  Unless you hate this property, or want to buy something you can’t afford without selling, that would be my plan.

I'm guessing that posting this buried under 200 "Me too's" will be less effective than a new post, but here goes anyway:In the U.S., how many times do these logbooks get scrutinized? 

Second thing would be to work with a contractor, this is great stuff to do since you know building a house, building material costs, and knowledge of right and wrong what to do. 

CA maybe as high with their EIR requirements that cost 250k to 500k just for the EIR reports.

Ultimately, it’s essential to consult with your lender to understand what’s best for your long-term goals and costs involved.