Leebo is correct, any meaning synonyms added on WK are shown in the KW question.
Likewise any KW answer synonyms will be accepted on subsequent attempts (adding 少女 to 女の子).
The one-to-many mappings will be somewhat ameliorated soon by showing parts of speech, great for i-adjective vs na-adjective, verb vs suru-verb etc. Not as helpful for nouns.
The greatest trouble is definitely in the lower levels since there are far more multi mappings (girl, father etc), I haven’t added as many KW answer synonyms at later levels since the words are often more specific - but mostly because I padded WK meaning synonyms as I did lessons (which is a beneficial learning exercise as well!)
For example I augmented:
決 “Decision” -> "Decision, Vote"
決定 “Decision, Determination” -> “Decision, Determination, Verdict, Call”
And they will also show up (soon) as:
Decision, Vote + “Noun”,
Decision, Determination, Verdict, Call + “Noun, Suru Verb”
Adding to WK meanings takes some extra work, but everything I augment I remember better anyway since I’ve spent that little extra time differentiating the words.
Haven’t really come up with a solution for the broad WK meanings like “girl”. We decided against manually adding to WK’s meanings ourselves, since the functionality is already there for users.
I don’t get too bothered if I answer the “wrong” one anyway, if I consider it a match I’ll ignore the incorrect answer and move on. I’m sure there’s some words I’ve answered “wrong” every time but have got them to burned through ignoring. I don’t see this as a problem either, it basically equates to Anki self-assessment if you choose to ignore and believe your chosen answer would have been adequate in a conversation/the context you were thinking of when you answered. Some I just take the hit and let it come back, it’s extra exposure, and only takes 1 second to answer anyhow.