Has a credit card, but never used it, paid everything cash.

We are not taking on any personal debt to pursue this journey; we don't have car loans, student loans, or carry credit card balances. 

(I’m aware of the strategies I’ll be taking in terms of increasing credit score through small credit card payments etc)For example, I live in NYC, a market that is infamous for being high-barrier entry, so I would mostly be looking at rental properties in the New Jersey area.

Using credit cards might be the way to go.

My concern with rent collection service is potential chargeback, specially if it's paid by credit card. 

For example, if you’re paying with a credit card with a total credit limit of $5,000, and there's a security deposit of $500, your credit card limit would then be $4,500 until the hold is released.If everything goes as planned, we’ll release the hold 14 days after you check out.Your reservation will be subject to cancellation—up to 36 hours before check-in—if we’re unable to place the authorization hold.

I've thought about plastiq.com or something similar to get cash from my credit cards for 2.5%. 

-Credit card debt $100k-Bought a multi-unit property in 2015, live in one unit, and did major renovations funded in part with credit cards.

I got started with $130k in balance transfers(credit card capital).

If you don't have the cash to finance the reno you could look it short term cash loans, your credit cards or more than likely the safest option of just selling it As-Is to someone who is more equipped to handle a project like this.