Warhammer 40k:Mixing Armies!?

Question

I have a Daemon Hunter army but I was wondering if I could mix them with any Imperial Guard Faction such as Cadian,Steel Legion Etc..

Do I have to have Imperial Inquisitors or could I mix them with Steel Legion?

Same for Sisters of Battle..Could I also mix them with Imperial Guard??

And if I do mix Imperial Guard with Daemonhunters do I need the codex for both daemonhunters and Imperial Gaurd or does my Steel Legion become Imperial Inquisitors?

If your confused ask me for more details!

Answer 1

I think with both armies you can induct guardsmen troops or just use your guardsmen as inquisitional stormtroopers, but you'll need the guard book to use them as normal guardsmen (i have no idea if they get their combat doctrines when inducted)