They do. In the shop they don't have tons of them available but they will order anything you want.
Pretty sure they do(I've never really looked since that's not what I build) I know they advertise Gundam products and sell paints/markers specifically for them. If they don't have it in stock they can special order it for you too.
I believe they do. They also sell paint markers made especially for them.
Thanks! Your answer is awaiting moderation.