As you said this is a first character, I'm going to give you some simple, core book only concepts.
A good major virtue is Major Magical focus - Art
While broad, I don't consider it an overpowered exploit, so I'd think most SGs would accept it.
The only issue with Magical Focus is the question "Is that in the focus". An example. It being a major virtue, I'd accept a crowd control spell called "Dance, Magic Dance" where a group of people must dance, would use your affinity, others might not (as SG I'd be happy with the David Bowie reference, and more willing to let it slide). While I know your design is magic artist, something to deal with the crazed mob with pitchforks if they show up should be considered.
Why is this virtue good for you?
It seems you want to do varied art in multiple mediums. You will need Terram for stone, metals and gems; herbam for wood, canvas and the like; aquam for paints; Imaginem for sensory thinks like smell, and for visual illusions; Rego if you want to move things; Muto for impossible outcomes that are clearly magic.
Due to needing a broad base of technique and forms, you probably wont have a really high form-technique combo. You'll likely have a variety of techniques and forms at middling levels. Adding the lower technique or form twice will get you to the same sort of numbers a specialist has.
Affinities are simple and really effective. 1.5 time the XP.
Consider affinity with craft and/or finesse.
You can have an affinity in a maximum of 2 arts. Think what medium you'd want to excel in. Wood (or canvas or any other plant product), Stone (or silver, gold, any metal, and or gems) or Paint, and choose the relevant form.
For technique, I'd suggest Rego or Muto.
As you are thinking Merinita - Faerie blood is a good option. Dwarf blood gives a crafting bonus.
There's 8 points of virtues, so it's a decent starting point. Pick some, pick all, pick none, whatever works for you.
A point of advice in spending XP on arts. While it looks tempting to get a bunch of arts at scores of 3 or 4, in game getting low arts improved is easy. An art can go from zero to 5 or 6 in one season. Generally go for an art score of 6+ or zero at character generation.