This is a technical support forum so I do not have price information. That will need to be sourced from where ever you plan to purchase your equipment at.
1. The board I would recommend to use if you already have the twist and mount patch panel to land all your wires on would be the 476TM-T12. This is a phone distribution board, you would connect your main incoming telephone line in to this board then it has 12 outgoing ports. Using patch cables you would simply plug into a port on the 476TM-T12 board then plug the other end of the patch cable into the port on the twist and mount patch panel you wanted to make active for phone. This would give you the functionality you are looking for to use some locations for data and some for phone without having to re-terminate.
Also PWB-58141 and PWB-58141-02 are not part numbers you will find in any catalog, those are manufacturing number that are printed on the circuit board and are not always specific to a certain product.
2. Yes, If you are adding a security system you will need a board with a security input port. The 476TM-T12 is has a security input port.