Not all CMs are. And the characters can even be CPs I believe, so I doubt it’s seniority. I imagine there are various factors - relative height compared to say Minnie of the CM “friends” for one. And I seem to remember wrangling over the weight of the Mickey heads, so that likely also factors in.
Maybe @ThorKat can chime in here?
My friend’s daughter was there as a cultural rep or whatever and she was friends with Eeyore, Pluto and Mr Smee.
Everyone is correct! To be “friends” with a character the first step is to fall in the height range. Then there is an audition process. A lot of full costumed characters are the same height so someone (even CP) can be “friends” with more than one character.
Also every CM (except CP) is allowed to join the union but you aren’t automatically in the union just by working there 
Can CP be a character or just a “friend”?
Google what being a “friend” with a character means in Disney speak
I daren’t. 
I do know the CMs that portray characters have to say they are friends of …, but in the case of the question I was meaning the CMs who come out and guide the characters
I thought the characters and the guides were two distinct roles.
I think the guides are called handlers?
The way I’m understanding @ThorKat
A) the handlers guide the characters
B) the handlers guide the “friends”
C) A = B
Yes they are! 
and you got the jist of friends.
CP can be “friends” and handlers
Sorry. I hold my cane out in front and usually just walk thru
My clothing has very little metal in it. Usually none at all. I’ve no replaced joints nor repaired bones. I carry a plastic water bottle.
My glasses are metal
Often an older security guy who sees me approaching will open the stroller gate and invite me to use that entry.
They don’t hate me in the sense I don’t invite it. The backpack I take with me has metal parts that always sets it off anyway, so I have my family put in anything that they’d have to hold out. It may not save us a lot of time, but I feel I get my “money’s worth” on going to the table when my bag has a glasses case, battery pack, and metal water bottles.
Briefly because, serendipitously, right after I actually noticed the first two letters there were posts about initials.
I mostly noticed the Villarejos. For awhile
Guilty!
Oh! Lol. I have said it a few times before but I also understand what it looks like 
I have a veerryyyy llooonnnnggg married name. Early on, I adopted my initials and last name. So technically it’s D.R.Villarejos. But my email is just drvillarejos and I use that for almost everything.
Edit: I mean I wish I was sometimes, lol. But that’s a very stressful profession. I did think of being a R.N. right out of highschool and working towards an admin in medicine position. But I can’t handle the sight of blood… so I went the opposite direction and went into design, real estate and construction. I just naturally know numbers amd understand aspects of finance and bookkeeping so a few extra classes and I’m borderline managing a few businesses at the moment. A little more complicated that that but I can be a Rehab Dr. if it fits. 
Re: pools, my MO for many years has been to sort of go in up to my knees, in beach or pool. I just hate getting my face wet, and usually I’m taking tons of pics and don’t want to get my phone wet. This is really enough for me unless I’m realllllyy feeling into swimming that day–but I still love going to pools and especially the beach.
Related: I was on a work trip to a Gaylord hotel in Denver and went down the lazy river by myself one night. By which I mean I was literally the only person on the entire lazy river.
It was weird.
But fun.
Random thoughts from a bench at Pop Century @ 645 am:
It’s fun to watch the resort come to life.
The queue for the sky liner, which must open at 7:00, is already back into the Pop Century hotel. I would estimate the weight is 10 minutes…and building fast.
The food court doesn’t open till 7:00.
I can’t get coffee for 12 more minutes.
What is Disney thinking? See previous comment regarding coffee.
Also I would imagine they’re missing out on a lot of grab-and-go sales for people trying to book it to a super crowded day at the parks.
That’s all for now!
Edited to add:
Skyliner cars started moving at 6:50. Station opened at same time. No guests being transported yet. Queue still building.
I almost drowned when I was a kid as well. The thing with the lazy river is that it’s moving. So getting in and out of the float/tube can be stressful. I recommend doing it at the entrance/exit point rather than walking through the river and jumping on an empty tube that comes by.
And sometimes - many times? - closes before the all the parks have.