As long as you have Kiki, Resto, and the three listed above those I think you have all the essentials. Exarch is the next one on the list you would need to add but it is definitely tougher to squeeze in there. It is a decent blocker though so it isn't absolute garbage. I wouldn't add Guard or Bell-Ringer ever.
I would rather have a cheaper flying creature with flash. Pestermite isn't that exciting but it is essential if you want to support Splinter Twin, in my opinion. I really wouldn't add Twin without adding the whole package to support it.