Best play period. Best is combination of all skills. I've started a freshman over a senior catcher because the freshman was the best. I've also turned an OF into a catcher because the catchers in the system just could not handle the mental part of the game.
I'll make some mad but will post some other opinions as well. One year the parents of incoming freshmen wanted to talk. They wanted to know if the freshmen would be given a fair chance to make varsity. The reason for the talk was some of the local TB coaches and private instructors who said that these freshman players were so much better than the varsity players. The TB coaches had pointed out all of the tournaments that these players had won and of which the previous players had not won. My child was a senior that year. I called her over and asked her how many local tournaments her team had won. She said one. I asked her how many local tournaments her tB team played in. She said one. I asked her how many states had her TB team played in that year and she said 9. Then, I asked her about the how her TB team had done in a national tournament in Chattanooga that had over 100 teams in it. She said 2nd place. I told the parents that a lot of the varsity had been playing in those types of tournaments but that their children would get a fair tryout and chance to make the varsity. One freshman made the varsity, and to be honest, those parents weren't at the meeting. Their older daughter had been playing all summer with mine.
Per coaches and pay. Having been there, the loss of coaching pay hurts more than what has been represented here. It isn't just the lack of getting a couple of thousand dollars in a year's pay. It is cumulative. For many districts like the one I coach in, once you reach certain years of service, you get additional increases. Also, that coaching pay matters a whole lot when a coach finally reaches retirement.