I'm not sure I have answers as such but in response to 2) I'm not sure different types of transference indicate progress or a lack thereof.
I also don't think different forms of transference are necessarily experienced sequentially either, although I think they can flow from one to the other.
An example I have is that I experienced very strong ET towards a male T AND I felt much better able to trust him although it took a long time to get to that point. That was over 10 years ago now.
I am seeing a female T right now and I have both positive and negative feelings of maternal transference towards her. Trust is a much bigger issue.
It's my opinion that the transference in my situation is different for lots of reasons. I think there's a gender and age element to it perhaps. My male T all those years ago was closer to me in age whereas female T could at a pinch be old enough to be my mother, although she would have had to have got started pretty early!! I think that has paved the way for maternal transference feelings to come out. I also think I did not associate male T with a maternal, more a paternal figure and the dynamic between my dad and I was very different - so the feelings that were elicited between male T and I were more to do with the unfinished business related to my dad perhaps? I'm not so sure on this one.
The one thing I would say is that I don't think erotic transference and maternal/paternal transference are necessarily completely separate things. For example with my male T I wanted him to be both a caretaker and a partner - those feelings were sort of all mushed together. It's worth thinking that language and words are just a way to try and define things to try and make sense of them so all these terms can be are approximations, rather than fixed "truths" which I know doesn't exactly help with the frustration when trying to think about it because it feels like trying to nail steam to a wall.
I'm sure AG has a good explanation somewhere of why the parental feeling can tip over into the erotic but my brain is a bit woolly today so I can't remember which post it is.