Yes, you would have to cook your ham after brining.
I slowly bring mine up to a temp of 74 deg C, and using a thermometer probe I will wait until the internal temp of the ham has reached 74 deg C, the same as the water surrounding it. I keep it at that for 1/2 hour and then take it off the heat and just let it go cold whilst still in the water. I generally use water with a bay leaf and some peppercorns in it. I never let the water boil, just sort of poach the ham.
I don't press mine. When it is cold I just cut the skin off and then cover with honey & mustard powder and roast it until this turns to a glaze - honey does burn easily though.
Yes, you will need to brine for longer if you don't inject as you will want the brine to penetrate throughout the meat. Injecting just speeds the process up.
I'm sure others with more experience than I will be along shortly to elaborate on my comments