For now, if he were mine, I would just continue to practice him and run singles.. and your are totally right, no Bully's on the field…..
You may just find that it is the time of year that is distracting him... many B Boy's are "stupid" during breeding season, neutered or not.... my boy, neutered at 3yr, knew quite well that it was breeding season and still does at 17+.
Do you run him with a muzzle? Many times that will help to keep the focus on the task at hand instead of bumping and playing...
Also the fact that you are running him with his housemates/friends that he typically plays with, is also a distraction (possible)... and if he is not totally focused on the lure then he thinks they are out there for play time.
I would (if mine):
1. Put on a muzzle if he is not already wearing one
2. Continue to practice him alone and ask the lure operator to keep the lure right under his nose... even to the point of letting him almost catch it... to get him really focused on it.
3. Don't run him with Lola as being a housemate might keep leading to him wanting to bump and antagonize her
4. Wait till well after breeding season to see if that changes anything in his focus
And in the end, some are just like that... my OJ has never coursed (except the other dogs...ggg)... he was sure that the only reason that he was out there was to bump and run with the others (I only ever let him run with bitches that I knew in practices and would not be put off if he did that)... and when he ran alone, he would get totally distracted if the lure was not right under his nose.