Can you explain more your concerns on this?
My ministry went through the switch to in-ears many years back. For musicians, those who don't mind having over the ear style headphones typically won't mind using shared headphones. For those who prefer in-ear style headphones, they can personally provide their own.
To help the rotating team remember to bring their in-ears, I provided a tackle box with their names in it that they can store their personal in-ears at the church.
During our service the praise team is up and down on stage at least 3 times. Now I'm just assuming, but I anticipate they would complain about being tethered, and I don't know if wireless would be in the budget. I do like the idea of storing their personal in-ears at the church for them. I'll bring this up and see what they think.
Thanks for all the other input from everyone else. I've already turned down the main instrument (piano) in the monitors. I will look at the EQ, but I don't think our board has the ability to EQ just the aux send. The EQ is where my skills as a sound tech start to wane. I really appreciate insights such as this.