I wasn't able to find where this is mentioned, so I thought I'd ask here.
How much can a summoner change how their eidolon looks? Can an angel eidolon vary its non-game appearance and go from one form to another? Can a devotion phantom change its clothes so it looks fancy, camouflaged, or armoured? And if so, how often can they do this?
Or are they entirely mutable as far as appearance as long as their crunchy statistics stay the same?
(Personal opinion is that they have to look like 'themselves' but can vary ornamental bits as needed, like ornaments, trinkets, clothes, et cetera. Notwithstanding the summoner sigil that they always show off.)
When you choose your eidolon, you also determine its appearance and general form, within the parameters for that particular type of eidolon. Once you establish your eidolon's type and general appearance, these features can't be changed later, except by selecting special evolution feats that can cause your eidolon to develop new features.
So the Eidolon initial text says that Eidolons appearance is defined in it's creation only and when adquire new evolution feats.
That said PF2 is a very flexible game that even allows retraining to change almost anything of a char. So as GM I don't see any problems to change eidolon appearance in any way and if this appearance change has some mechanic change it can be made normally inside retraining rules (just give a good flavor excuse like you and your eidolon link and will becomes stronger during a recess and this made some definitive changes in your eidolon or any thing you want and talk to your GM to you both come to an agreement on how it will better fit into the adventure).In the end there's no good balance or mechanical reason to prevent you to do changes in your character, even Eidolons.
Personal opinion is that they have to look like 'themselves' but can vary ornamental bits as needed, like ornaments, trinkets, clothes, et cetera. Notwithstanding the summoner sigil that they always show off.
Pretty much that, yes.
The type, mechanics, basic shape and form, and attacks available are decided at the start and can't be changed other than when leveling up and taking additional feats.
But other than that, the Eidolon can change its appearance as much as any player character can.
When you choose your eidolon, you also determine its appearance and general form, within the parameters for that particular type of eidolon. Once you establish your eidolon's type and general appearance, these features can't be changed later, except by selecting special evolution feats that can cause your eidolon to develop new features.So the Eidolon initial text says that Eidolons appearance is defined in it's creation only and when adquire new evolution feats.
That said PF2 is a very flexible game that even allows retraining to change almost anything of a char. So as GM I don't see any problems to change eidolon appearance in any way and if this appearance change has some mechanic change it can be made normally inside retraining rules (just give a good flavor excuse like you and your eidolon link and will becomes stronger during a recess and this made some definitive changes in your eidolon or any thing you want and talk to your GM to you both come to an agreement on how it will better fit into the adventure).In the end there's no good balance or mechanical reason to prevent you to do changes in your character, even Eidolons.
"appearance and general form" & "general appearance", so some of the cosmetic changes listed in the opinion of the OP would be allowed. I wouldn't think the Eidelon could do such any more than a regular PC, as in they'd need to go get a haircut, change their clothes, etc. like any other normal creature w/o shapeshifting powers. Viewers should still recognize them unless other factors come into play, like applying a disguise, but yeah, there's no inherent ability to alter an Eidelon or for it to alter itself.
Maybe via retraining, though it's worded so strongly I'd say no, except an MCD Summoner could do so by training out of the MCD then back in, right? So that'd be a bit unfair if the Summoner itself couldn't, though it'd be a worst-case scenario IMO re: time required though I'm still inclined to prohibit it unless their were real-world considerations.Example: I'd had a true arachnophobe player who would've been unable to function with another PC having a spider-like Eidelon on the battlemat. I'd had to change spiders to poisonous beetles, etc. after that first spider encounter which funnily enough was their second monster ever, right after they mentioned how lucky the last monster hadn't been a spider. "Ha ha." (Hyperventilating) "Oh crap, you're serious."