Rabbi Dov Lior said that strictly speaking it is permitted to hug an aunt, and what Maimonides and the Shulchan Arukh wrote, that it is improper, is not the strict law. (It also seems to me that Rabbi Melamed said there is no prohibition in this regarding a sister or an aunt, and that some of the amoraim practiced this way.)
Does the Rabbi agree, and in his opinion is it permitted to hug an aunt / cousin / sister?

In my opinion, obviously yes. After all, touching that is not affectionate is permitted.