If Malinin told USFS he wanted to go senior, and they said/implied/gave advice to him to remain in juniors and, whether explicitly or implicitly, let it be known they'd bury him if he didn't, then it's entirely on them. But it wouldn't have been because he then couldn't earn spots for Jr. Men at Jr. Worlds (if it is held), because as long as he is age-eligible, he could have done Olympics/Jr. Worlds/Worlds like Nam Nguyen did.
And, yes, I think that if Malinin wanted to skate in seniors, and USFS was, at worst, neutral about it, they would have given him at least one early good assignment that wouldn't have been in the middle of or close to JGP's, and then, if he did well, they would have sent him out to more. And he would have focused on one version of each program.
I just don't see where Brown has all of that power: he's not politically connected by coach or club. And while it's nice to have a back-up for the Team Event, there's no obligation to split any discipline, just a max of two splits. TV doesn't care about Men. And if they had appointed Malinin to the Olympics and Jr. Worlds and had given Brown Worlds, the reverse of 2014, or had assigned him to 4C's, from everything we've seen of him, he would have accepted graciously. I haven't seen a retirement announcement, but if he is wavering, he might have stayed even in another year after being passed for the Olympics, since, the last I read, Chen and Zhou are planning to be in school full time next year, with Chen expected not to compete, and with Zhou's first full-time school+skating experiment getting mixed results.
In the end, his choice was fine since he made Group 3, same as Brown. Once there they could choose either man.
And that worked out well for him re: OWG exactly how?
Had he chosen to go senior, and USFS wasn't blocking him, he might have placed himself firmly in Group 2, making Brown irrelevant.