Sugestion of what might be really happening with this two:
First, I’ll mention some things that every person who ships Yoonmin might know just to remember this important things. Suga in previous interviews has mentioned that his perfect “person” is someone who likes his kind of music and with good taste on headphones (I know you already read this, so it’ll be fast). Every single member mentioned that they like a “girl”, but he said “person”. Besides, those interviews where he said that he didn’t like the question of “if you were a girl, which member you would date?”, and in Cypher 3 he mention that he don’t care if he is with a boy or a girl. I can continue with this, but it was just a brief reminder of Suga being gay or bisexual. Now, this is the good stuff and the theory with the most recent info. I want to believe that Yoongi actually told Namjoon about his love for Jimin, because he seems to support this a lot. Everyone trust their lider, so maybe in a really deep talk, he told him his secret about this forbidden love. We can see this a little bit more notorious in Serendipity, which RM (I’m still not getting use to this new name, btw) composed for Jimin, which might be a love song to Suga. All members joke with that, including RM. Even in a game, they started to tease Suga because he chose Jimin only to hold his hand. When Jin said that, everyone became quiet like when you said something that is true, so nobody laughs at it. When the boys where in an interview, they were asked what does true love mean to them, RM added that “they don’t have a BOYFRIEND or girlfriend and they want to date someone…”. Maybe he said this on purpose, taking the advance of being in the USA, where they are more open minded with the LGBT community, having in mind Suga’s love, because we know he would NEVER said something like that in Korean TV. The sad part of the story. It is more than obvious in the way Yoongi looks at Jimin that he is in love with him, but Jimin knowing this or not, he is not. This is only one sided love. Jimin do love Suga, but in a really fraternal way, and that’s why Namjoon is giving him a little bit of help. Jimin might really get along with Suga, and they do a lot of physical contact, but Jimin does not look at Suga the same way he does.
I don’t know, this is just a theory. Don’t take me too serous.