Definitely NOT Rostratus, completely different body shape and pattern. They had it mislabeled or confused. Rostratus is a rather distinctive Hap.
Definitely Protomelas type, and does seem like a Red Empress though it is hard to tell if it is exactly a Red Empress since there are many related Protomelas, and fish are often kinda "vague". They can mix types, and a F10 may not seem the same as a F1. Why are you thinking it doesn't look like your older Red Empress?
He has more of a pointed snout i guess you could say as well his coloring seems to be more of an orange. Definitely does resemble it the more i look at them though. My Red Empress is like 6" and pretty dominant so hard to tell with the contrast they have.
Starting to look pretty good, definitely a male. I still think its a protomelas taeniolatus. There's numerous collection points, with numerous different colors. Some have no red at all. Which one is it? Here is protomelas taeniolatus "fire blue", which looks pretty similar to yours.