不愁 basically means "not worried", to answer your question, I think you are looking at it the wrong way.
First of all, I think the confusion is between the using of "不" and "没", you are thinking that by adding the word "不" or "没", the sentence becomes negative. But it all based on the context you are using it in. Lets compare the examples you provided:
不愁找不到工作 vs 不愁找工作
"不愁找不到工作(Not worried about not finding a job)"
"不愁找工作(Not worried about job searching/job hunthing)"
The two sentences may translate into different meanings, but it all comes down to the same general idea, that is "Not worried, I can find a job(or maybe I don't need a job)". And that is why the sentences basically means the same thing.
不愁没钱 vs 不愁钱
"不愁没钱(Not worried about not having money)"
"不愁钱(Not worried about money)"
The two sentences also have the same general idea "Not worried, I have money/I don't need money)", so they mean the same thing too.
So theres no negative or positive words that you need to follow with "不愁", but instead it all based on the context. For example, if you are paying for someone and they are reluctant for you to do so, you could say "啊呀，不愁钱(lets not worry about money)" instead of "啊呀，不愁没钱(lets not worry about not having money)" as it is abit more informal.
I know this all might seems confusing, but 加油，咱不愁，会越来越好.