The other part of this is that in addition to this, we are borrowing from our home equity line of credit to put down the 20% deposit- so we have that payment too.   

If you have equity and decent credit, a conventional Fannie Mae HomeStyle (or the Freddie Mac version) would likely be the better option instead of an FHA 203k loan (which will require a 3rd party HUD consultant to oversee the deal in addition to having the contractor involved). 

Is there a way I can "co-sign" with one of my parent's credit cards and be on their credit history in order to boost my credit score? 

Be mindful that there are rules that the lenders want you to check off.Furthermore, there are other rules on the tax side where you want to normally be under to get the most tax benefits.The magic number in both instances is '14 days'Lenders want you to stay atleast 14 days to meet the secondary home requirement.The tax accountant normally wants you to stay less than 14 days or 10% of the days it was used as a rental to treat it as a rental and not as a personal residence.Best of luck!

I'm told the screening criteria credit score is on the higher end .But most of the listings I see are also on the same league.

For context, each tenant has a separate security deposit escrow account.

They should have and accounting department, maintenance department, leasing department, tenant relations, property manager, assistant property manager and legal (in house or 3rd party).

@Katie Camargo I would consider: HELOC or Cash-Out Refinance:Post-closing, the higher appraisal gives you the potential to tap into the equity via a HELOC (Home Equity Line of Credit) or a cash-out refinance.

You’ll need to treat it like a business—handling tenant management, accounting, legal compliance, property maintenance, and more.That said, when done correctly, it’s a powerful tool for building wealth!

Quote from @Argel Algura: Hey Bigger Pockets Community,A year ago I wrote about rebuilding and starting over in life and considering real estate investing as a path (see post here: "Bad credit, minimal cash and starting over in life . . .