This method, though not as exhaustive as a professional CSS, is suitable for smaller properties and still yields meaningful tax benefits.

If the neighborhood is suitable, I would scrape and build new.

That will tell you your ROI on doing the upgrades.If that's a suitable figure, do them.If not, don't do them.That's really what it should come down to.

I would first find a market that is suitable for you and showing signs of potential market growth.

Seller financing, lease options, or partnerships are alternative routes that might be suitable for your specific circumstances.Establish relationships with local real estate professionals such as agents, lenders, and contractors.

Consult with a mortgage broker to assess your specific financial situation and find the most suitable loan option.Since you have $50,000 in equity in your current residence, refinancing could be a way to access this equity and use it as a down payment for the new duplex.

However, we negotiate a suitable timeframe with the seller for the tenants to vacate the property.

I have heard of a 1% dp, conventional, owner-occupied loan but again that may not be suitable for a jumbo loan. 

FNMA may not be far off as concerns "coverage" suitable for the lender... but you and FNMA need to think about all the actual elements in play here.

Ensure your pricing is suitable and in line with other similar properties in the same area so as not to get lost should the prospect filter the listings.