You are starting that freshman center when Miller (your best big man) is coming off the bench. Did you really promise a start to Mason? If so, that's a big no-no unless you absolutely have to due to a battle AND it's not causing you to bench a guy that needs to be starting. If you didn't promise him a start, get him the hell out of there.
You really need to work on team building. You need to balance out your team more as far as position/classes. You just brought in a five-man class with all frontcourt players. You need to have an eye towards roster composition that goes 2-3 seasons out, so that at any time you'll have a mix of veteran bigs and guards, with younger guys backing them up. You don't want a situation where you have all veteran bigs and all young guards, or vice versa. Just gives you glaring weaknesses that everyone will pick on. Also, it's going to result in seniors who aren't even in the starting lineup. It's crucially important that you make full use of your upperclassmen and that they're in the starting lineup. If you've got seniors coming off the bench in DII, that's reflective of bad decision making when it comes to team building.
Same for various skills ... you want to project out and know that, a couple seasons down the road, you'll have enough perimeter shooters, enough good rebounders, etc.
I think you need to be pickier in who you recruit. For example, the pf you're RS'ing had 28 rebounding. You are simply better off taking a walk-on.
I know these are more big-picture items, but I'm more in the "teach the guy to fish" camp. There's already been good breakdown as to the various shortcomings of this particular team. And since I know you're an OTR guy, 549 is anemic for a human-coached DII team.