I'm looking to start a Death Guard army pretty soon (Typhus is in the mail

along with a box of
CSM ) and I was reading through the codex and saw that Death Guard isn't allowed to take any Chaos marines or bikers. Bikers I can live without, but how am I supposed to have an army without any infantry? Would it be ok to just convert my
CSM's to Plague Marines? Or is that a given? What about raptor squads? As you can see I'm a little confused as to how Chaos works, so any help would be appreciated. Thanks!
-Coop
P.S. If you feel like helping a bit more, I could also use some advice on a fun 750pt list to run with.