Even the wholesale deals rarely are good enough for BRRRR-ing.

From there I will build up my commissions until I have enough to house hack.My little brother also wants to attend Purdue, so if I find a deal good enough, I know I can get financing help from my parents to purchase a multiplex while I live there house hacking, then he can live in it in 4 years.There are a lot of places around Lafayette IN that would likely do well to BRRRR, so I can get some more cash to continue from there.That's my current plan, and given that mine is concrete rather than hypothetical, if anyone is interested in seeing how this plays out I'd welcome you to stay posted on my journey!

If you're credit is good enough to qualify for a loan, and you have some knowledge and hopefully some experience in real estate, you should be able to find a passive investor at a real estate meet up, REIA meeting, etc.  

The bottom line is if you find a good enough deal, you will find the money as well.

How much would be a good enough down payment if I would get a property worth $299k, for 4 bed, 3 bath, 1,690 sq ft?

So you have to ask yourself is that good enough?

If it is 45-60 days are doing well, if this is shorter than you are in a position where you are either priced too high or the condition is not good enough (or both).

It is unlikely that the deal would ever be good enough that I would do a deal if the new investor brought no funds of their own.

If the deal is good enough, using private money or hard money, letting the seasoning period pass, then refinancing into a bank loan is an option, as well. 

Just need to make sure you get a good enough deal on the purchase.