Quote from @Zongfu Li: An agent named Mathew Dial contacted me for loan opportunity and told me how flexible and how easy they can provide bridge loan lending and conventional lender.

Ideally I'd like the ability to invest in individual stocks of my own choosing (fractional shares is a plus), a diverse option of index funds, and ETFs.Has anyone found a great banking option to have the most flexibility with your HSA investments?

I use strict / flexible cancellation policy.

It is flexible though, in that I can roll it into any IRA at any time.

You'll have more flexibility with non-traditional lenders, traditional will all follow the same Fannie/Freddie guidelines.

Since this is my only property I do not mind and with my flexible schedule I am able to spend time doing this. 

I know it's not as flexible as a HELOC but as long as your deal flow is good and the tenants are paying the mortgage you won't come out of pocket for it. 

If I was not starting from scratch, like I did myself, I would buy SFHs because I prefer their long-term flexibility, relative scarcity, and multiple exit strategies to MFH.

The 25% has to be your funds.Now, there are non conventional options that would be a bit more flexible but even most of those programs will require at least 20% down with no second mortgages filed on the property. 

Private Money Loan: Private lenders might be a flexible option, especially if traditional routes don’t work.