Personally, I think your problem is a lack of self-esteem - I notice your worries that you're hogging attention more than any actual attention hogging; basically, you're freaking out about nothing and, yeah, I know how anxiety is but I still can't help but worry.

Regarding Surprise, there's nothing wrong keeping a "straight man" character who doesn't really need a lot of development or CR to function; that's kind of what Bon Bon is for me, as an example. Maybe you could start slotting Surprise into things where the situation calls for just random pony interference as opposed to a specific character.