How to chnage flights in airport?

I am flying from DME (Moscow) to FRA (Frankfurt) on LH and then FRA-DFW (Dallas) on AA, 2 different tickets.. I am getting different answers from these airlines on following- 1. Can I check-in my bag from DME on LH all the way to ORD even though my connection in FRA is on AA given that LH and AA have interline agreement? 2. I dont have an airport transit visa for FRA airport. LH will check me in only till FRA and then at FRA I have to re-check in at AA counter- I hope AA counter is inside international area for me to check-in as I dont have visa to go out all the way to departures? Please advise.