Yumiko, which was popular in the 1960s/70s, is an entirely different name. In Japanese, Yumiko and Yumeko would be considered as different as John and Shawn.
I'm not really qualified to say that Yumeko is or is not a "normal" name. All I can say is that I have never met or heard of anyone whose name incorporates the word Yume (which means "dream"). However, in the last few decades parents have been using all sorts of creative and newly coined names, so it wouldn't surprise me. However, your other suggestions (Yumea, Yumeka, Yumeri) strike me as more contemporary than Yumeko. Modern parents don't use "-ko" names much at all, but those other endings are quite popular among children and young people.
This message was edited 6/15/2024, 6:09 AM