There are specific requirements for the solo401k.You must be a business owner with no common law employees and earned income to supplement the 401k plan.

All those things require maintenance. 

I had to rescind the offer as this is my first investment property and I don't have any experience/enough knowledge of potential damage and fix required.

DSCRs don't require employment history, income or DTI information. 

For example, effective drainage is essential to avoiding future problems and maintenance expenses.

Also, make sure your AC’s are in good condition and if they need some maintenance, do it before it gets busy in the summer!!

Foreclosures require knowledge and experience to win.

Before finalizing the deal, I'd like to get some opinions on whether this amount is too low or too high.The renovation projects are minor ones, such as painting, window work, kitchen renovations, some repairs and corrections that do not require permits.Thank you!

In most cases, the lender will require the person who is providing the capital to sign for the mortgage.

Others may have a different opinion, but outside of a seller carry back up to 90% CLTV (still require some skin in the game, unless you go true hard money) 2nd liens on real estate for purchase transactions in the manner you're seeking are very difficult to get a loan against, whether it be a secondary market lender (private equity fund, balance sheet lender, family office, etc), and usually are seeking larger transcations ($1-3MM +) in this space, and are still capped at a max 75-80% CLTV (still wanting skin in the game).# 4 usually requires more explanation as its newer to the market (DM me if interested in discussing these options further), but all 1-4 appear to be potential options for you based on the limited details.