Here's my 2 cents...
I am "friends" (ie. amicable) with all of my exes (none are As). I don't talk to them on a regular basis, or hang out - but when the occasion strikes (birthday, see something that reminds me of them) - I call. I chit-chat and enjoy the moment and then move on. Nothing more, nothing less.
The problem with alcoholic/codie relationship dynamic? Is it is NEVER that simple and clear. So, for me, I'm in the process of divorcing AH. We have two small children so I don't have a choice to go no-contact. I will make things amicable and interact with him as it pertains to the children - but don't know about being "friends" with him. Too much history, damage, hurt, resentments, etc.... for right now.
If he were to recover (and we get some SERIOUS therapy!!) maybe I could have a decent conversation with him... but like Thumper said...
My concern with that is it would put me in a position to always protect my boundaries - always.
There is no break or vacation when you're involved with a toxic personality. It's HARD work. Can you do it? Sure, but at what expense to yourself?