Have you tried taking them early int he morning? When I was on it I set an alarm and took it about 4 AM, went back to sleep for an hour and woke up ready for work. It never gave me problems falling asleep as long as I monitored my bipolar and didn't take it when hypomanic.

I don't know about combining it with coffee as I gave it up years ago but it may not be the best except very early in the AM.

Just my experience; everyone is different.