Can a straight girl and trans girl work in a romantic sexual relationship?
No, not for long. Eventually the trans girl will transition to the point where the straight girl sees "woman" and her attraction goes away.
Can a bi-curious girl, who has never had a romantic sexual relationship with a woman, and a trans girl work...?
Yes, almost every bisexual woman was once a bi-curious woman, who had one or more "trial" relationships with women before she was certain she was bi. So it is quite possible that a trans woman can be the first woman a bi-curious woman has fallen in love with, and the first she has slept with.
Outside the traditional world of exclusive monagamous romance leading to exclusive monogamous marriage, there is a whole world of ethical sex-positive relationship behavior to explore.
One kind of relationship in that world is "friends with benefits". When it is important to you both to preserve your friendship, more than it is to pursue becoming each other's one and only for ever and ever, you can enter into a FWB relationship, which is more likely to survive life changes and attraction changes than a traditional romance can, because the friendship is always predominant and the WB part can be mutually dropped when it doesn't work out.