I actually do feel like Skip beat is a good one to suggest to people who know nothing of manga since it has good writing, good characters, like no fanservice really, enough of the out there humor to get them aquainted with some japanese tropes but not really? it's just a really good manga that i managed to get my whole family into and considering that includes 3 brothers with varying acceptance of the romance genre that's pretty good odds? idk

Perhaps. While I think Punpun is very good, it caters more towards a specific audience. It would be a good gateway manga for people who are into psychological and coming of age stories, but I can think of better/more suitable gateway manga out there.