My understanding is that there are usually good reasons why not each active check can use all macros. In this case opening check_http for the macro $_HOSTADDRESSES_4_1$ should not pose any pitfalls, so this is a reasonable (rather small) feature request.
But it might take some weeks until implemented and backported. If you can live with this, it would probably be the best approach for this exact problem.
PS: And, yes, expanding the macros with the lists of whitespace separated IP addresses here clearly is a bug. Please mention this when reporting the missing macro expansions, since then it is more likely to be treated as bug.