Immediately with a signed lease it what the seasoning period of 1 day is referring to...so it depends on the lender.

My first fix and flip will close in 60-90 days (short sale) in Howard county.

I would only by a home with window units at a big discount with the mindset that shortly after purchasing I will be adding central a/c.

Has anyone had any experience with lenders that will still do HELOCS for short times on deed or does that matter?

In short prepare, prepare, and prepare.  

This is okay if you're doing just one and need cash in short term, but keep in mind you won't be getting mortgage prices. 

I have a private investor that intends on investing $100K for a period of 5 years with a 10% return with an option to receive all investment after 3 years.  

Has anyone had any success marketing to people that are in redemption period?

If you are planning to rehab to resell and the money will only be tied up a short time, cash is a great idea or you could look into a hard money loan, however those can be extremely expensive.

Don't sell yourself short, you seem to be doing ok already, you reached out here!