Hey @Sheldon Vic
Congrats on grad school! No easy task with a young family.
Three things to consider; how long will you be in Hawaii, will you rent the property or sell it when you leave, will the refinance be a cash out refi?
1. How long will you be in Hawaii
I totally understand wanting to avoid rent. You'll want to run the numbers in a buy vs rent scenario. Often times the magic number seems to be 2.5-3+ years. This is the point in which buying makes sense financially . If you're only going to be here for a year or two, I would recommend continuing to rent.
This is assuming you sell the home when you leave Hawaii. Local economists and experts are expecting little to no appreciation in the next few years. Any significant appreciation will come from forced appreciation. So if you sell when you leave, natural appreciation will likely not be sufficient to offset the closing costs, meaning you may end up losing money on the deal.
Above, you had mentioned worse case scenario being you break even. I think worse case scenario is you lose money. We are at a treacherous time in the market. The market is fickle right now. Neighborhood to neighborhood, property type to property type are all varying. Some are up, some are down. This is when people lose their shirt on short term holds. You can still make money, but you or your team have to know what they are doing and be disciplined. Anyone could make money the past eight years. Now we'll start to see the market teaching some really tough lessons.
2. Will you rent or sell the property when you leave
Selling when you leave was addressed above, and will depend largely on how long you'll be in Hawaii.
If you are going to rent the home, you'll need to go into it (during the house hunting process) running those numbers. One challenge will be finding a home you want to live in that will also make a good rental when you leave. The majority of the time (in Hawaii) it's difficult to find a home that fits both bills. Rentals that make financial sense often do not have the features an owner occupied home would have. Similarly, homes attractive to owner occupants often do not make financial sense as a rental. Live where you like, invest where you'll make money.
This is another reason why I might recommend not buying now. Save the money and buy a rental in Oregon.
3. Will the refinance be a cash out refi
If you're here for a year, there won't be much equity to pull out. Even after a few years, I wouldn't anticipate much equity. At least not enough to offset the cost of a refi. Not with where the market is going. Also, if it's going to be a cash out refi, the numbers might not work from a cash flow stand point. If you pull out the max amount, your higher mortgage payment will likely push you into negative cash flow.
If you are set on buying a property in Hawaii (which is a good idea if you think you might come back) then I would buy something strictly as an investment, and have your family keep renting until you leave.
Your realtor has their work cut out for them in running these scenarios and analyzing potential properties that fit your short and long term needs. If you end up buying a rental, do not buy a single family home! Realtors love having their clients invest in SFH. Not sure why, except a higher purchase price means a higher commission. SFH in Hawaii are a tough product for long term rentals.