How old is the cast in wmebsd? Umineko tells us their relative ages (Krauss is 2 years older than Eva who's 3 years older than Natsuhi) but not when they were born so there's room to shift their ages up and down a bit for narrative convenience. (Rudolf and Rosa have a little more evidence and can be inferred to have been born in 41 and 53 respectively)
sorry for taking a little while to answer this, it involves numbers and MATH.
I'll start by saying their ages in wmebsd is one of those things i kind of purposely left a little vague, since we ourselves in the canon source don't have any confirmed years for all of them. The best we can do is take what little information the story does give us and work around that.
Eva says herself she's 3 years older than Natsuhi, and I don't remember if it's ever actually stated anywhere that Krauss is 2 years older than Eva, but i do have a very vague memory of that being mentioned somewhere? maybe the manga. If you have an exact moment where it's said, please share it with me because i've always had this memory of seeing it but can't remember where it was. With that in mind, I think most people generally figure Eva's about 50, so Krauss would be 52 and Natsuhi 47. The story takes place in 1986, and Jessica is 18, but it took Natsuhi 12 years to have her in the first place, so that's 30 years right there. This would put the year at 1956 and Natsuhi at 17.
Now, this is just assuming Natsuhi is 47, she could be older than that, but working with these numbers in mind, I think it's a pretty good estimate. It also wouldn't surprise me if she was married in only at 17 :/ Or she was married in pretty much right after graduating school, so 18. Given all that, though, I will say in wmebsd, I always intended that Natsuhi is at least 18 years old. Definitely 18-20.
I'll admit, for the case of Rudolf and Rosa, back when I first started wmebsd, I hadn't really stopped to take the time to try and estimate their ages as much, and rather I actually just took inspiration from a lot of other fanworks at the time. (I assume the listed years you gave for when they were born has to do with years involving when Kinzo moved them all to Rokkenjima and working with that in mind? Please clarify if you don’t mind, as I’m quite intrigued actually, but don’t remember all the established years the game does give us </3)
If Rudolf was born in 1941, that means he would be around 15 in 1956, but I always age him up in my mind and have him closer to Natsuhi's and Eva's age. If Rosa was born in 1953, then that would make her about 3 in 1956, which is actually a little bit younger than I imagined when writing the fic, but accurate in that she is supposed to be very young.
With all the canon guesstimating out of the way, it’s pretty clear it’s still quite difficult trying to pinpoint exact ages and years. I do wish Ryukishi would give us confirmed numbers, but at the same time, it’s kind of nice having that little bit of room to work with. Even with all that in mind, I never actually said if wmebsd takes place in 1956, all I ever said in the fic was “She had only recently married into the Ushiromiya family”, but that could easily still be a around a full year, making it closer to 1957. Again, I kind of purposely left certain things a little vague to work with canon.
With all that in mind, and what I said about Rudolf and Rosa, I intended their ages to be something like this in wmebsd, give or take:
