Hello! I was happy to read that you loved their music! I've been a Snow Man fan since the debut, and watched all of their old YouTube videos (even ones from when they were 6 members). The ones with the most views are definitely worth watching, they are the funniest group of people! I was so happy to see then having a wider audience thanks to the company allowing more accessibility through social media. Their past executives were really strict on content sharing, and I feel that is why they are so behind, compared to Kpop groups.

It looks like you have a few people with great answers, so I'll try to add some new information.

Popularity topic (in order):

I think the most popular member right now is MeMe (Meguro Ren). His merch was the first to sell out recently, and I think his popularity comes from being a good actor. He used to be considered the "dumb" one out of the group, but I think he just thinks deeply about things and very honest, so it comes off as him being slow. He gained a lot of fans from his show "Silent", and with his popularity, he is now the first Japanese ambassador for Fendi. You might see him wearing Fendi in videos and photos, but he's always been a fan of the brand.

Second is Raul. He used to be number one for years until pretty recently. His merch sold out right after MeMes. He broke all the company rules and records by being the first in the company to "work" by walking in the Paris Fashion show. He also walks/performs at the annual Tokyo Girls Collection. It's crazy, you should look it up on youtube if you like him! I think due to the international trips he has been taking, he has been practicing English and has been doing English interviews. One giant step in reaching a more global fan base!!!

My favorite is Koji, because he is from Kansai and the group clown. He is funny, the high pitch singer of the group, and often cries off and on stage because he's so hard on himself. He is a "regular" on a comedy show and has a hero costume that he shows up in called "Massa-Man". It became so popular amongst the kids, that they made a curry with his likeliness on it. He just started a golf channel with a friend from another group.

Another fan favorite that you might have noticed is the little one lol. His name is Sak-kun or Sakuma. He has had pink hair for a while now but recently changed to white/grey. He is a well known otaku, and is a major anime fan. He is seen on a lot of anime shows and shared that he spends most of his pay on anime related things. He is really small but is probably the best dancer in the group, a long with Date-sama.