A: Hey, here is my answer:

Is leaderboard included in any appsumo plan?

Not at the moment. We do not exclude giving LTD users access later, as we have done for some other features, but with no guarantee.
So consider it as a No, to not be disappointed.

Add on cost for views packages?

We have a monthly package starting at 199$/month. But if you need more than 200k users/month (not views because a user can view a story several times) that means you have high traffic, and our Enterprise plans are more suitable. Please contact sales team.

No way to control and set limits on views by domain?

unfortunately not, it"s not something we will implement soon; Limits are account-based

We have a free trial available, we encourage you to try Snackeet to see if it meets your needs, as the product is available today with all the current features :)