Your good, the only thing a FOID card does is allow them to buy firearms and ammo (you don't need a FOID to buy reloading components) If you have a LTCH you can buy ammo in Illinois.
Your good to go . Just don't get out at a gas station etc with your firearm loaded u less you have an LE ID carrying under LEOSA
An Indiana LTCH is not required to purchase ammo, in Illinois. An Indiana driver's license is. (Proof of residence)