here is a good thread on getting Eternal Pets. further in the Thread, there is an update for 3.0.
for farming teams, just remember that you only need to have Luck & Item Drop on the Hireling, all other farm affixes you use need to be on the Main.
for more DMG, for the Main, since it has lots of space taken up for farming, survival would be second priority, and then DMG. if you have a lot of Sets for farming, see how much Crit DMG you can do, and maybe Glasscannon, since it can be rolled with Ruby, and figure out which Element you like to use best. for the Hireling, it will be doing most of the DMG, since only a few spaces are needed for farming. any attacks your Main has should be in support of the Hireling and maybe have some kind of CC. Characters that die make the game feel longer.
do a Search on farm teams or farm main and hireling. there are a lot of good Builds. if none of them are what you are looking for, they should give you a good idea of what would be good for what you do want.