this is the weirdest question. honestly, you can't even play the companions before meeting the protags because that just delves mostly into headcanon territory and no one wants to deal with that sort of thing.
typically, most people play with their own protag in mind. this is not law, but that tends to happen. if you're speaking in terms of memes, if a protag tags a companion, usually you go with that as the companion's protag. obviously things can change up a bit -- we already know alternate worlds are a thing that exist in the da world -- but people usually talk about it beforehand if you go the route of the companion not knowing that particular protag (personally, i've done it a few times and it can be fun).
in games, i always app in with my own world state. my companion knows his/her own protag(s) and won't deviate from that. there's always the conversation about companions not knowing the protag (which does get kind of old after a while, but part and par for the course playing from canons such as this), but can be handled well if the protag player isn't one of the special sect who get pissy and passive-aggressive if your character doesn't recognize theirs. aka if you're playing the protag side: don't do this.
this sort of thing is really a choose your own adventure. there's no "right" or "wrong" way to play it. just communicate your wants for the thread/cr.
Re: DRAGON AGE
typically, most people play with their own protag in mind. this is not law, but that tends to happen. if you're speaking in terms of memes, if a protag tags a companion, usually you go with that as the companion's protag. obviously things can change up a bit -- we already know alternate worlds are a thing that exist in the da world -- but people usually talk about it beforehand if you go the route of the companion not knowing that particular protag (personally, i've done it a few times and it can be fun).
in games, i always app in with my own world state. my companion knows his/her own protag(s) and won't deviate from that. there's always the conversation about companions not knowing the protag (which does get kind of old after a while, but part and par for the course playing from canons such as this), but can be handled well if the protag player isn't one of the special sect who get pissy and passive-aggressive if your character doesn't recognize theirs. aka if you're playing the protag side: don't do this.
this sort of thing is really a choose your own adventure. there's no "right" or "wrong" way to play it. just communicate your wants for the thread/cr.