If your going to go for these option, the most attractive is option 2.
I also have Alexi in my league, and he has been up and down throughout the season. Dunn is a someone you can easily dispose considering you have Pujols. IMO there is alot of buzz is about how bad Hanley is playing right now, so this is the time to buy if you can. Dunn is going to get you HR's but you have that already locked (Pujols, Upton, Kemp).
Option 3 is also attractive, but after looking at your team you would be giving up Scherzer for Cahill. If you did that then you will have 3 A's pitchers on your team. Being from the bay area I like that A's, but I wouldn't want to have 3 of their pitchers on my team. So on that note I say option 2! I like Anderson way over Gio, and if Mccarthy is on the waiver wire, pick him up. Hope this helped.
If you got time, Let me know what you think about my situation: viewtopic.php?t=430387