timmmay:MikeB4: I would recommend the minimum CPU being i5 with your requirements but you should look to buy in the i7 range
i5 should be just fine, i7 not really much faster - though I'm talking about desktop processors, not about the specific Surface Pro models. Basically four cores is plenty, adding hyperthreading or more cores only helps for some operations.
The difference between i5 and i7 for what is needed here is not speed, granted speed between the two is fairly close, its about task handing especially dealing with RAW etc and photo processing in PS and LB, it's why I suggested an i7 it would
provide more raw grunt here.