Guinea pig separation anxiety?

Hi everyone! I have 4 beautiful texel guinea pigs..1 male and 3 female..2 of the females are the babys (now 7 months old)...they are all great pigs i just have some questions. first is one of the sow kids is suuper shy, runs away when you try and pick it up and does not purr when you pet it. just seems a little odd when all my other guinea pigs love being picked up and purr and just overall love human interaction. any reason why this is? my second question is the black boar seems to be very moody. Sometimes he is very aggressive/ territorial and other times it seems like hes nice. i notice when i pet/ hold the others or clean the cage he will chatter his teeth( like every single time). this is the only pig that chatters his teeth. should i give him to a responsible owner( a vet that wants him) because he loves human interaction just has his weird points which i don't know what sparks it. if i did get rid of him will the 3 sows get separation anxiety and vise versa. will this effect them negatively. And my last question is i use towels/ fleece as bedding, but i recently realized that 2 of my pigs pick at the towels.. like they eat the soft fuzzy stuff...what is this behavior all about/ why are they doing this? is there a way to prevent it. i recently got them some willow chew sticks and it seems like they have stopped. Thank you for everyone's help