LH is miserable in coach -- just like US. With UA you can UG on LH for 35K FRA-India (H fare or higher) or 17.5K for a full fare ticket. But that does not help you.

I was thinking about going to India last January and contemplated flying Emirates in business rather than burning 70k miles on an $800 FRA-India ticket. They only charged about $1600 in C class round-trip FRA-India. Check out their website. In any case, it was better to split up the tickets rather than booking USA to India.

If you fly UA to FRA then you can fly Y relatively comfortably in E+ on a cheap ticket, and don't have to worry about upgrading that part of the trip.

You can collect non-status UA miles on Emirates.