I take a more optimistic view. I expect that coaches might look for, say, one catcher in the class of 2017. Coach might identify 3-4 catchers that fit that bill and make 3-4 offers, or might offer their top choice, failing that go to #2, etc. Once one catcher accepts the offer, I expect the coach to stick with that catcher. If the catcher doesn't develop, then they might renegotiate, but I don't expect the coach to continue recruiting catchers and dump one for the other and continue to attempt an upgrade until signing day. I don't think a coach can survive operating like that. I just believe that success depends on integrity and relationships. Can't do it that way, IMO.
Sure you can... Most try to bring in multiples of players each season in whatever fashion they can. I have see fall season college teams with 30+ players of which 15 were freshman.
You have to remember the drop out rate as for each year. You can't HOPE that C you recruit is good enough because she might not like the workload in college, realizes her parents can no longer force her to play, realizes that she isn't gong to see the field this year, hate classes, hate the school, hate her teammates, etc, etc.. Many players quit before their first game. Many quit after a season or during a season. Some quit as juniors/seniors for a variety of reasons. Rosters are in general freshman/sophomore heavy.