When I started out, I leveraged my credit instead (because the rate to borrow was so low) BUT the reason for this was in case something went wrong, I could handle the payments for a bit if need be. 

How to know if lenders, met thru BP, are legit

Simply borrowing $ would be a lot more cost effective. 

Hard money lenders – Best for novices or borrowers with a bad credit scorePrivate money lenders – Best for novices or borrowers with a bad credit scoreBank financing – Best for experienced flippers who have a great credit score, capital on hand, and significant collateral.

David Pierce is an attorney that many hard money lenders require borrowers use because he is considered one of the best. 

The only problem you may run into is having enough funds for down payment/closing costs, so a co-borrower may be required and/or you can obtain gift funds.Another possible solution would be to go FHA route and find a fourplex.

I understand that you cannot use borrowed money for a down payment on an investment property, but I was wondering what if you took out the loan for a vacation or something else, let it sit for 6 months or so, and use it for the 20% down payment.

Purchase Price:$129,000.00 duplexPurchase Closing Costs:$2,500.00Estimated Repairs:$1,500.00Total Project Cost:$133,000.00After Repair Value:$129,000.00Down Payment:$32,250.00Loan Amount:$96,750.00Loan Points:$0.00Amortized Over:15 years Loan Interest Rate:5.500%Monthly P&I:$790.53Total Cash NeededBy Borrower:$36,250.00Monthly Expenses: $1,519.86 Monthly Cashflow: $325.14 Pro Forma Cap Rate: 10.38% NOI: $13,388.00 Total Cash Needed: $36,250.00 Cash on Cash ROI: 10.76% Purchase Cap Rate: 10.38%

Do you need to borrow money in the next few years?

Eligibility is dependent on borrower income and census tract which you can google to find out.