Hello.
You should be able to play your save without issue, but the names are definitively gone.
Naming the girls was possible in the earlier version of the game but I removed that option, as you noticed.
I've talked about it somewhere else, but long story short, I needed to control Cassie's name for story purposes.
I agree that it's a weird thing to do, and I thought a lot about it before making that decision. Quite frankly, I initially allowed it because it was kind of a common feature in the visual novel sphere, but as time passed on, I came to realise that it was, at least for me, creatively limitative.
I'm sorry for the inconvenience!