I don't know how to answer the poll. None of the answers seems sufficient. Powers first, I guess, though that seems insufficient.
Reading through your post I agree 'powers first' is appropriate. I also agree that it is insufficient.
To be frank, I look at your first character concept and think "dang, overthink things much?"
Always.
1) I've played a cleric and fighter most recently; I want something with spells. I always play clever characters. I did a "big bang" wizard a while back, so sneaky clever spellcaster is what I want.
2) Beguiler looks cool.
3) These 3 races are options. Talk to DM about level adjustments and such; go with tiefling (no LA) because sneaky clever spellcaster overcoming evil influences is fun roleplaying.
4) DM wants to amp things up. Add swashbuckler as a gestalt, and start at 3rd level.
5) Figure out stats (one person rolls; we all use those numbers arranged as we like). Cha is my dump stat; Int and Dex are both freaky good. Con and Wis are good; Str is normal.
Azae is the daughter of two crime lords with the blood of fiends in her veins. She was a rich daddy's girl groomed to take over the family business, but realized her parents are cruel and self-centered people. Intellectually she thinks being good is a better and more interesting challenge than being evil; emotionally she desperately wants to be Good, but overthinks it and is terrified of "screwing up" because people who screw up get killed. She's frighteningly smart, but comes across as cocky, brash, and bossy. She manipulates people out of habit; a general sense that it's more effective than trying to explain things in terms "normal" people can understand; and because she can back up her threats.
That's really cool. You have provided one of the more detailed templates of your process in the thread. Thank you.
Overall I think it is pretty strongly prioritizing WYCD over WYA. There are a lot of clues to that:
a) You waited on the background to last rather than writing it first and then figuring out the mechanics.
b) The primary decision as to what to play this time was based on ensuring a contrast of WYCD compared to what you played last time. You did not prioritize playing contrasting WYA. For example, you could have easily written, "I played a cunning cruel manipulative SOB last time, so this time I wanted to play a gentle softhearted lout."
c) Your mechanical choices seem to have been made more for an eye toward what capabilities you wanted to have, rather than the personalities and beliefs of the character. This is however where it starts getting complicated.
I think you a) set up a binary that isn't really there for many people, and b) your language in OP slights the mechanical option.
Yes, and yes. I don't actually expect a complete binary to exist for anybody, but I do expect to see certain general trends as to which side of the equation weighs as most important and is addressed first. And I'm slighting the mechanical option because I'm currently a bit frustrated by my inability to communicate WYA and its importance with new players.
So while I agree that either/or is inadequate here, nonetheless you presented and wrote the character background last and in general, if someone asked you what your character concept was I don't think it would be your first thought to rattle off your characters background. In fact, the strongest element of your character concept was, "Not a cleric or fighter." That was the primary driving force.
Still, what is also interesting is that you are right, little bits of WYA started sneaking into the process at a fairly early point. "I always play clever characters." is both, WYA and WYCD, albeit it seems to be less narrative or expression motivated than it is self actualization. And tiefling could have been motivated by a mechanical cause, but instead you went straight to WYA: "overcoming evil influences is fun roleplaying" with full on dramatic/narrative goal of play. This suggests that tiefling has strongly communicated "WYA if you choose me". I personally hate the race because its a walking one dimensional stereotype, but at least it has that going for it! (Stereotypes are not all bad.)
As for what I'm overthinking right now, it's thinking about how to make that feedback more effective at generating non-stereotypical WYA from your WYCD choices and vica versa. I'm thinking about how I could write a PH type book with the goal of teaching new players to develop more sophisticated WYA and incorporating it into their play.