In my opinion, a well rounded team should have at most two closers. However, I could understand an argument for three closers.
Getting back to your question, if your league is not a keeper league, then I think you could most certainly get more for zigi then Morales. If the league is a keeper league, I like the move. Morales is a switch hitter, whom is coming into his own the more games he gets under his belt. I mean lets face it, zigi is a soft throwing submariner. I just don't see him lasting the whole year as the A's closer. Not when they have closer stuff waiting in the wings in the form of Bailey. If I were you, I would sell zigi as a closer while I still could.
I've never really been comfortable with lindstorm closing either. It seems to me that sometimes he throws too hard for his own good, as evident in his disaster last week, or the week before that (please forgive my memory lapse). Inge on the other hand has sleeper written all over him. Yes, his average is going to drop, but if you look at the past, he usually starts off well, and falls off later in the season from the pressure of being a catcher. This year, he's the everyday third basemen. I think Inge is in for a career year myself.
Both of these offers make sense, but obviously I would take the latter one if it wasn't a keeper league.