No, Aminu is far too dumb to be a starter. I don't care that he's (finally) playing well - dumb players should not be starters. Also, Aminu's defense is overrated. He's not bad by any means, but there isn't a player in the league that thinks to himself "Oh no, I have to go up against Aminu tonight." Except for his penchant for losing his man (which, thankfully, he hasn't been doing in the POs) and committing stupid fouls, he's a slightly above average defender - nothing special. The only thing that's good is the fact he can switch on screens.
As much as I'm NOT on the Vonleh wagon, I prefer starting Vonleh at PF if we're able to get a C like Howard/Cousins/Drummond/etc. Vonleh doesn't have 1/10th of Aminu's confidence, but he's a smarter player - and if he ever gets confidence he'll be a better player.
Unless we pull off a miracle Harkless is our starting SF next season. I'd LOVE to get a star SF, but there really aren't that many, and the few that exist aren't donning a Blazers jersey anytime soon.
But if Harkless is our starting SF then we need a new starting C and PF. We can't start Harkless/Aminu/Plumlee or Harkless/Vonleh/Plumlee, or even Harkless/Vonleh/Howard...well, not unless either Vonleh or Harkless make an unbelievable jump over the summer. If either Harkless or Vonleh become a reliable outside shooter then Harkless/Vonleh/Howard could work.