If I'm reading you right, you're considering a two-stop itinerary ATL-SEA-OGG-KOA, on AS ATL-SEA and HA SEA-OGG-KOA. You need to arrive at KOA by 5:30, and you'd rather spend $400 than $800. I completely agree with everyone else here that trying a 45-minute connection from AS to HA in SEA is nuts. Playing with Google Flights a little bit, you do have a challenge leaving ATL the morning of 2/4, but there are a number of options in your price range if you're willing to leave ATL the evening of 2/3 and overnight on the west coast. If you're not willing to do that, the biggest thing I'd suggest is looking at making your last connection in HNL rather than OGG. You'll have a lot more options for KOA flights and easier recovery if you miss the connection.