Also, once on title, what are my construction loan options?

You'll be negative every month.As mentioned above, you can't do a clean seller finance (where you get the title at closing) unless you put down $80k to pay off their existing mortgage.  

You will want to make sure the title is handled correctly to remove both husband and wife and also make sure the chain of title is clear and has no "floating" judgments.  

On title it shows up as a UCC lien.

Your title and post are a bit unclear, @Andrew Carson.

Rahul, I have about 10 you can talk to. you'll also want to have an equity partner with new build experience so you can get the best terms. most of ours are national lenders. we doing joint parnterhsips for new builds and take a small interest in a single purpose entity for example:Rahuls New Build LLC (95% owner)Pink Development and Construction LLC (5% owner, no voting or distribution rights)Take title to "Miami New Build Limited Partnership LLC" which is a single purpose entity. 

As for selling with 10% down at 8% interest, you now have two title transfers that violate the due on sale clause and add complications to subject to “safeguards” that reduce risk if note is accelerated, if party in possession doesn’t pay taxes or insurance, and of triggering whatever system the lender has set up to notify them when a deed transfer takes place. 

Be sure to provide ample due diligence for delivery and review of seller records and extended periods for appraisal (and review), title and underwriting.- As with any RE transaction, it's best to consider the other parties perspective when determining feasibility.

Another suggestion someone gave me was being the bank and act as a private lender at 8% to 12% interest - you would need to vet the investor and project carefully and financial transactions are done through a title company. 

PURCHASE PRICE AND MORTGAGE: I purchased the property for $270,000 put 25% down, and it appraised for $290,000.There is a complete identical property to mine directly behind my unit and it sold about a month ago for $280,000 the same day it was listed.