I don't use my phone for photos, I'll have separate camera for that, so I'm happy to leave my cell phone behind. I have an InReach Explorer+ and it works great as a stand alone device, and does so in all weather, as the buttons are easy to operate in gloves or mittens.
If the Mini 2 can send custom messages without the need for a cell phone, I would consider migrating over to the Mini 2, because it's half the size, half the weight.
Having some rando cell number assigned for the InReach communications hasn't been a problem, and it's been the same number for a couple of years. I don't know what the number is today, exactly, but it's been consistent enough that people on the receiving end have had no problem following along. This includes a lot of strangers, because people I'm traveling with, or random people I meet along the way, will sometimes use it to get messages out to friends and family.