What an interesting jacket, I can totally see why you're confused! I love the pleating on the sleeves, they're gorgeous. The hand stitching on the lining made me wonder if it could be antique, but the lack of wear on the outer fabric and lining suggests it's more likely vintage rather than antique. Also, although frog fasteners were used in the Edwardian era, these ones seem more modern, and don't quite fit this jacket, so I think they were added later. The inner hook & eye fasteners appear to be the original closure.
It does have a slight costume vibe. Perhaps it's a tailored vintage 50s peplum, later adapted. You mentioned the astrakhan collar had been added, and I think the frog fasteners and black trim were likely added at the same time - possibly for theatre or costume use. I also noticed the back of the jacket bunches slightly near the trim just above the peplum, which could indicate the trim was added later.
Another possibility, as you say, is that it’s a well-made handmade piece in a reproduction style. However, the combination of hook & eye closures with frog fasteners makes me think it could be a bit older and was adapted for costume use. If it had been made for a costume, I'm not sure both types of closure would be necessary. So, my theory is it could be a mid-century jacket that was adapted later for performance, but I'm really interested to hear what others who know more think! Do the hook & eyes show any wear, or do the inner poppers for the collar have any markings?
