I can't tell from the pic what the new polyp is besides a zoa lol. As far as the zoa with the bryopsis growing on it, if you can remove them and place on a new frag plug, I would suggest doing that. Another method you could try is raising your magnesium levels. This article should help explain the process https://reefhacks.com/bryopsis-fluconazole-dosage/#tab-con-12
I'll try remounting. I accidentally had my Mg around 1545 for about a month and still had bryopsis show up around that time on a snail's shell. I'm afraid if I adjust it again my corals will be peeved and they just hit their stride. I think I just hit mine as well. haha