They will need extra 10 people at most
Karakurt has complement of 39 while Steregushi has 99
It's not even close
Depend how long you want to use during deployment.
If you plan to use it for days like a corvette is used you will need crew rotation inside the ship so you can multiply by 2 the total crew.
Missile boats are use for a couple of hours just to fire their missiles and their air def system is just to defend themselves during those couple of hours.
I think they know exactly what they are doing
If they knew so well they would have asked the original karanurt to be increased in size to fit 2 uksk. And they would have asked to increase the number of uksk on gorshkov from the start. And they wouldn't have 3 or 4 different steregouchshy variant in service.
They are screwing up and it's time to replace the decision makers because if those mistakes happen with destroyers, cruisers and carriers there won't be a new serie of ship to correct them. They will have unwanted big ships for the next 40 years.