Hood and Collins.
I've bought into the Simons hype train, and I think the plan will be to bring him off the bench in a Crabbe/Connaughton/Hood (from last year) role. He'll be told to look for his own offense first and pass second, and CJ will run backup PG. (I know it's not a popular idea for CJ to run backup PG, but it's probably what will happen. As Simons gets more comfortable, the hope is the roles reverse and Simons takes over more PG duties, but that isn't going to happen on day 1.)
Defenses tend to put bigger, rangier guys on our guards, and often hide their point guards on our SF. Hood notoriously feasts when he gets a matchup on a shorter player, though, so that plays right into his wheelhouse. So you start him at SF.
Whiteside can give you 28mpg at center. The other 20 minutes will be Zach.
I think you have to start Collins in a Noah Vonleh kind of role, where you give him minutes and see how he produces (and if he fouls). If it looks like it's going to be one of those game where he's going to foul a lot, you sub him out early and bring in Tolliver. And you save Collins for the rest of the game as just a backup center. 22-24minutes.
If Zach looks good, well, then he's going to get 32-38mpg, because he's young and agile and you ride that horse as long as you can just for his defense.
Tolliver's role expands or shrinks depending on how good Zach looks.
Portland will play around a lot with all the new wing toys coming off the bench, but I bet Bazemore gets the majority of minutes when the dust settles.