There are no racial restrictions on the romance, but Tashia is neutral good and will not join parties with a low reputation.
She is more powerful than Kelsey -stats and spell selection wise- and have a figurine of a spirit leopard - Peanelian - which has some extreme immunities, best not to use it. Don't forget to pick her up early to have control over her spell choices. She is lethal in combat if you know what you're doing. Note that the loot at the end of her quest is totally unbalanced (amulets of power, 2 Malakars..), NOT good.
Her romance is quite long and she have many lovetalks (who can be accelerated without messing the game), usually you don't reach committed state before chapter 6. Pay attention to a certain dream when romancing her.
The romance comes with a twist and is overly well done, you don't have to babysit her, just be nice. Make her a gift from a shop in the Promenade. You can also try your wits answering her riddles.
Tashia is endearing and fun to play, one of my favorites with Amber and Tyris Flare, but only interesting if you romance her, a bit bland otherwise, so when you don't want to romance her and don't need a sorcerer leave her at the pub.