What are some different options to get about $300k for for the construction which should take less than 6 months to complete and get the refi?

thx for the ref John.sub market with good secular trends, good cash flow, and  attractive tenant pool are some initial reasons for exploring Terre Haute.

What are the other options for the property that can generate the most income?

This is a good option. 

Other platforms that do the same are include RentRedi, Stessa, Avail, Innago, Apartments.com (formerly Cozy), and TenantCloud.If you want to go a more traditional sense and work with a more mature platform that doesn't bill your tenants you might look into Rentec Direct, Buildium, Appfolio, Propertyware, or Rent Manager.The best way for you to figure out which is going to work best for you is to explore their free trial (if offered).

I'm exploring options within the financial contingency outlined in my contract.

What are some options to get an ADU loan on this property?

I am struggling to find the right option for a HELOC on my second home in Northern Michigan.

I think you have a few options. 1. 

When bringing up subject-to as an option, the agent kept stating that his loan was un-assumable and that there was nothing more outside of traditional financing that could be done.