To set it up, you would need to link the controller with shell storages/constructors, by right clicking, to link the controller with a shell storage/constructor, you would need to right click the controller and shell storage/constructor with a sync core, shells that are finished will automaticly be transfered to a shell storage if there is any un-occupied shell storage.

The Shell constructor controller would control the shell constructors, it would have 2 modes, you would change modes by clicking a button on the GUI.

The first mode is the demand mode, in that mode it would automaticly make shells if there are more storages then shells/characters (the non shell player) available then it would start making shells and if there is a shell done, then the shell would automaticly be transfered to one of the linked storages.

The second mode is the redstone mode, in that mode, it will start have a number in its GUI of the amount of shells stil needed to be made, every time there comes a redstone pulse to that controller, that number would increase, as long as that number isnt 0, it will start building shells, everytime it starts a shell building process that number will decrease.

No.

If someone were to make this as an addon, feel free to install said addon, but now, no. The entire reason the shell constructors and shell storage units weren't merged into one type of block in the first place is so that the player HAS to move the shell out manually.