converting stem shifters to brifters
You can buy any 7 speed Shimano brifter (or compatible ones made by Microshift). The ones you link to are fine. The front derailleur needs to be Shimano road.

You'll need:
- Cable stops on the downtube
- New cables and cable housing (brake and shift)
- Probably new bar tape

The tools will be cable and housing cutters, an awl, a file and some screwdrivers/hex keys. 

Not sure what you mean by cable tensioners.