What do you have a 2 yo and 4 mo wear to a funeral? I don't even know where to begin and they definitely don't own muted colors right now.
I'm not in the whole "must wear black to a funeral" camp so I would put both in something nice but not worry too much about colors. If we had to go to one I would either have my guy in a button down or sweater because those are the nicer things he has even though neither is black.
I agree with @kvruns and @MrsMaryK2016 that nice over colors makes sense as long as you're not in anything too bright.