I would not support all-trans shortlists.
Apart from what Eamonn said about many other minorities not getting their own shortlists, it needs pointing out that (unlike, say, deaf people) 'trans' is a very heterogenous category that has no objective qualities for membership. It's based completely on the individual's say-so. It's a PR move by the trans lobby (a very successful one) to cast all trans-identifying people (let's face it, they mean TIMs) as vulnerable and marginalised. When in fact when it comes to TIMs the opposite is often the case - many are wealthy white men who have spent half a lifetime accumulating power and money off the back of their white, male upper-middle class privilege.
I saw someone on twitter saying that 'transwomen' had never had even one MP, so what were those privileged women complaining about re the shortlist? This demonstrates the power of the word 'transwoman' to reverse the reality of sexism: 'transwomen' (i.,e., males) have been in Parliament since the beginning of Parliament. Unlike, you know, actual women.
Further, I would not want a shortlist designed to promote people who subscribe to what I consider to be a very anti-woman, anti-child and anti-science ideology. I would only consider voting for a trans-identified candidate if he or she had specifically repudiated current trans ideology, for the same reason that I would not vote for Christian candidate unless I was sure that he or she did not subscribe to fundamentalist Christian ideology. Otherwise I would worry that once in power they would do their best to enact policies that hurt women.