I would highly recommend lootas. They're pretty much mandatory in horde lists IMO. Another battlewagon for your other nobs would also be a really good idea.
Units that you can probably toss: stormboyz, warbikers, and kans. The stormboyz and warbikers are too small to have much staying power (especially the warbikers) while the kans are too slow to really help much.
However, using the kans and deffkoptas as your ranged anti-tank isn't terrible. You can probably get by without adding lootas, but lootas are better than both of those units for killing things because they can hit targets across the board without putting themselves in harm's way.