For Marriott you get 10 points/$, Plats get 50% bonus.

If you'd like to max out your points, then you might considering getting a Marriott Credit Card. I think in general you need fewer points to redeem a MI property over HH, however you also earn fewer points per stay.

From what you quoted for points required to stay in Hawaii, for Marriott 40k a night is a Cat 8 hotel and I don't think all Hawaiian properties are Cat. 8. You can pretty much get anything for 40k points/night, except the Ritz. Also one awesome thing about point redemption for Marriott: book 4 award nights and get the fifth free.

Room upgrades with Marriott has been a hit and miss I think - if you check the threads here at FT.

In order to really enjoy Marriott's perks for elites you need to stay at FS hotels, for lower end hotels like Courtyard - there is no free breakfast as a default for anyone - regardless of your status.

About redeeming your holiday in Hawaii - I read previously here at FT that in Hawaii - a lot the guests in Marriott hotels are Plats and are celebrating something. I think this is just a norm in Hawaii regardless of which chain.

Hope this helps.