It’s definitely a difference between Israeli/French Lubavitchers and American ones. The Israeli’s seem to go more extreme for the look I was describing. I think I can safely say I’ve never seen an Israeli Lubavitcher with their shirt tucked in (at least when they’re visiting America; I don’t see them in their natural habitat).
The tie thing I don’t get, and shluchim always seem to avoid the subject. Lubavitchers over the age of ~60 who were “old school” Lubavitchers and probably speak Yiddish all wear ties as glued to their necks as their hats are to their heads. Yet, the younger Lubavichers will flat out say it’s against their minhag to wear a tie. It doesn’t make any sense to me.