My canon ends up being a combination simply because I try not to read any guides or spoilers on my first playthrough and just go with my gut reaction to events. Inevitably, those wily writers throw in tricky bits - dialogues that say the opposite of what you intended, evil choices that lead to positive outcomes and so on. So I go back and re-play several times.
I completely messed up my imported World State for my first run of DAI, so even though my first character would be my canon, I'm going to have to mess with all the choices again for DA4.
In general though, a red-headed female elf apostate mage is my canon character. I felt very dissatisfied playing as a human in DA2.
Ummm, details. I enjoy the romances, but there hasn't been one that kept me up at night, so I don't find them important enough to make canon.
DAO: female elven bloodmage, romanced Zevran, saved the mages, peace between elves and werewolves, Bhelen, etc.
DA2: female mage, sided with mages, romanced and saved Anders and did a happy dance when he blew up the Chantry
DAI: female elven mage, allied with the mages, romanced... I can't decide. The Cullen romance would be interesting if it had more oomph to it, simply because of the whole mage-Templar dynamic. I'm trying out the Solas romance, but it's slow going.
My alternate canon is a female elven rogue who gets to make the wicked choices, though I still can't bring myself to support the Chantry or the Circles.
But every time I look at Cullen I feel bad. He just desperately needs someone to love him T_T
I almost hate myself for this! Cullen is such an easy choice, and he's kind of Ken-doll and all of that, but I have such a hard time not flirting with him.