Maybe add composition, music history/literature, creative writing based on listening to iconic music, artistic students could illustrate music, tech savvy could create videos or use Acapella app to create their own duets/trios, etc that could be performed for your in-person rehearsals to keep them connected with their peers. Give them assignments that "help out" others. Have them make demo videos for younger band members and make connections...pen pals? Give them a purpose other than just being a part of the ensemble. A chance to develop leadership skills in another way.
Currently our district is allowing remote learners to participate in extra-curricular, about half of the band remote learners are coming to band camp. Not sure why they're remote learning but they're ok with their kid at marching camp, football games, etc.