@Account Closed he wouldn't necessarily have to tell the HML that he plans to occupy any of the units.
@Greg DeFeyter you've laid out a pretty thorough plan and it sounds like you have a good understanding of all the moving pieces. However, your strategy will be tough to execute for a couple of reasons
1) You might not be able to get HML loan at the terms you're expecting, plus interest rates are going up. It could be very expensive to carry that loan for 12-24 months
2) You need to also factor in your costs on the primary residence HELOC, which usually has a variable interest rate. Plan for that rate to go up as interest rates rise over the next 24 months.
3) Not only are the fourplexes expensive in the areas you listed, but also very competitive to purchase.
4) I'm actually not sure if you can refinance into a primary residence FHA loan for a fourplex that you already own. Plus, FHA has some other rules (self sufficiency calculation being one) that makes it tough to use that financing right now.
Frankly I think there are much better/easier strategies to execute right now rather than going to the MF route.