The Yamaha 75 and 90 are both on a 97 cubic inch block, and both weigh the same. The gear ratio is also the same, so the 75 is just a detuned 90. Thereby, your fuel consumption will be pretty on the higher side as compared to some other 75s.
Also, that hull may actually perform better with a lighter motor. On aluminum bass boats, the fuel tank, batteries, and livewell are all in the stern, and they don't exactly get up on pad like a glass boat (some of the performance aluminums do, but not the Stingers). All this weight in the transom will pull it down, then you are adding a lot more motor weight, without adding enough motor to really get the boat back up. If those are my only 2 motor choices, I would probably go with the 60, or buy the boat by itself, and put an F90 on it myself (dealer won't do it)..
Is there a reason you aren't opening yourself up to other motors?
The Etec 75 weighs 320 and has just the same pollution ratings, not to mention the 3 years no maintenance, as well as being a 2 stroke, after those 3 years, the maintenance will still be lesser. About the only downside is having to buy the boat and motor separately, as Lowe is owned by Yammy, but if you have a dealer that sells both Lowe/Yammies, and BRP products (evinrude) they should be able to hook you up with a package deal. Otherwise, you buy the boat with no factory prerig, and then take it to an Evinrude dealer, and he will sell/mount the motor.
The Honda and Merc 4 strokes are all about 380, so not much gain in buying seperate.
You probably don't want the carbed 2 strokes, but the standard Yammie two strokes are only 230ish for a 70. Not to mention it will be cheaper, but if you ever plan on selling, it probably isn't the way to go.