Yes, It's possible to date a transgender person and still be straight.
While it is true that technically speaking, It's impossible to change your biological sex, You're still able to change it to be more accurate to the gender that you feel like. By extension, It is fully possible for a straight man to be attracted to a transgender woman who had things such as hormone therapy. Now, That's not to say that you can't have preferences, I'm just saying that you're sexuality doesn't magically know whether or not someone was born as a male or female.
In conclusion: It's possible to date a transgender person and still be straight. If you're a straight man, You're attracted to feminine features regardless if the person is "actually a man".
I also have a complaint about how vague the question is. For starters, I do not know what is meant by "equally female", Considering being female is "yes or no" as opposed to being a scale. As for the second question, I can't speak for all men, Let alone with just a simple "yes" or no". I'm also not dating, But I still felt like contributing to this debate. If I misunderstood the point of the question, Or the question itself, Feel free to correct me. I am also open to criticism.