Hadn't noticed the previous answer but I've emailed Francesco at Fireforge Games and this was the answer
"We will release for Christmas 3 boxes of infantry and with these you will be able to make up to 12 crossbomen, up to 12 foot knights, up to
24 foot sergeants. There will be a box of dismounted templar infantry, a box of dismounted teutonic infantry and a box of foot sergeants.
We will release first, for november, our ruleset Deus Vult, the book that it's possible to see in the interview of beasts of war, is only a
beta, the layout of the pages will be similar in the definitive version. The size of book we are thinking for a format similar to the
other rulesets as Hail Caesar"
I hope this helped! Looking forward to the infantry!