Your pastor has let the guitars stay in place, for now, but if he has already nixed the keyboard, I would expect the other instruments will soon follow.
I would have a meeting with the pastor with the other musical staff and see where he is going. I have seen this happen at some parishes where a pastor has a particular preference and completely dismantles the existing musical program, much to the dismay of the congregation.
If he is flexible, different Masses can have a different musical accompaniment: some more traditional and some more contemporary.
Our parish works this way:
- the pipe organ is used at the 11:00 am Mass
- the contemporary group is at the 9:00 am Mass
- no instrument is used at the 7:30 am Mass, and
- the Saturday vigil Mass uses the keyboard with a cantor.
That way, there is something for everybody, but still one community. Hopefully, your pastor will keep an open mind. Good luck.
Ultimately, if you do not want to go with the same vision, and he is intractable, you may want to look for a new parish.