How would you play a mostly benevolent, Calistria worshipping trickster bard? Advice on viable builds, and trickster path decisions.

This is a two-part question, really.

First, builds: If you want to focus on the casting, performing and buffing aspects of the bard, but be able to drop into melee range to help flank and contribute melee damage in fights that aren't serious enough to waste spells slots on, how would you set up a trickster bard? I'm interested in possible 1-3 level multiclass dips that could be useful but am leaning toward a solid 20 levels of bard.

Second: This is a mostly good character with a vengeful streak, who would be drawn to the trickster path because of the reality bending, chaotic power. Still at some point I'm probably going to want to quit playing along with the unserious, dark games of Socothbenoth.

If you stop playing along with him as soon as you get the Lexicon and lose access to the wardrobe and the council, can a trickster still get to mythic rank 10, or will I get stuck at mythic rank 9 and miss my chance at the secret ending? I've played trickster before, but always the most stereotypical, nonsense loving, clownish version that does all the goofiest trickster options. I've never played a trickster who chooses that form of mythic powers but is actually mentally serious. Seems like it would be an interesting change of pace if there aren't progression drawbacks.