Which type of financing?

[Horace Grant]

I recently put a 3bd/2ba and 2bd/1ba $335k duplex under contract to house hack (owner occupant) and I'm wondering which loan option to choose. I have $90k in cash. I will rent out the 3bd/2a unit for $1500/month. Estimated monthly income = $2800/month after I move out (I know this doesn't meet 1% rule but it was the best value for the market I could find. It's a B-class, turnkey property in B-class neighborhood). Monthly capex/maintenance/vacancy = $375/month.

My options are:

1. 0% down 5-year ARM at 3.75% interest rate = $2300/month PITI ($5k out of pocket)
2. 5% down FHA loan at 2.875% interest rate = $2300/month PITI ($23k out of pocket).
3. 15% down conventional at 3.125% interest rate = $1950/month PITI ($56k out of pocket)

Initially, I wanted to go with the 0% down ARM. However, I am not sure if I will be living there for more than 1-3 years as an owner occupant as I have a girlfriend who lives 60 miles away and don't want to have to fork over the 25% equity in order to refinance as non owner occupant if I were to move out to her. I was thinking of doing the FHA so I'd be able to keep $33k ($56k - $23k) in my pocket but also not having to worry about refinancing. The only downside with this is that the PITI payment would be the exact same as the ARM. But then I thought I may as well drop the extra $33k to get a lower monthly payment and improve cashflow.

What would you do if you were me?