My question is should I try to get approved for an investment loan or conventional?

Conventional construction loan.

Conventional financing with a construction loan.

We need a healthy down payment, but luckily with the shift in pricing we appear to have a lot of room between what's left on the current mortgage vs. what the property will most likely appraise for...The main problem I am trying to tackle in my head right now is if refinancing in July when we close in October/November (and we will need/use conventional financing for that home) really a good idea?

The opportunity to make money might be their its just not obvious or conventional. 

@Mark Vesu I see your thread got highjacked a bit, I have a recommendation for a broker for you if you cannot do a conventional loan but I am actually working on a cash out refi for that same loan size in San Jose right now on someone’s primary home if you don’t have problems with DTI like many investors and can do a conventional loan, reach out to me and I can give you some numbers or pass on the broker

Maximum loan amount for preapproval would then most likely be 95% of an appraised value of 440k for a conventional loan, or if you've gone > 3 years without buying a home you'll qualify as "first time" so 97% LTV would boost your appraised price range to 733k. 

Commercial C-1 zoning may allow mixed use or retail on the frontage but this is a hard stop to gaining conventional financing. 

This is a rant about the nightmare that is getting a conventional mortgage at Chase and I'm not sure if this is the right place to do it but I want this to be a warning to any other investor that may be looking to use Chase especially on a deal that has a tight closing window.

My original plan was to save up money over the next year to pay cash and use the BRRRR method, however we have looked at a few properties and have considered just buying property with a conventional mortgage if we find a good deal in the area we like (we have enough saved for 20% down and light rehab).