Using HELOC as down payment along with conventional mortgage?

[Benjamin Trubisky]

My wife and I are trying to learn as much as we can about the RE investing. When we started dating, She owned a house that she bought as a foreclosure and rehabbed. Just recently, we bought a house with cash from her family's trust. We have renters in the first house and are taking $400 a month profit from that property. We plan to do some work to the new house and eventually rent it when we find another property to move into. We also came upon a 4 unit property that it fully occupied and up for sale. Wel like the place but don't have the cash in hand for the down payment. Would I be correct to think that we could use a HELOC to fund the down payment and use a conventional mortgage for the rest? Then a year or less down the road we could refinance to pay back the HELOC and combine both to a conventional mortgage?

Or would we be better to look for a cheaper SFH property that we can use a HELOC for full purchase price and then refinance?

Thanks in advance!