If you can get to everything from underneath, it's no big thing to relocated the electrical lines. As for moving the plumbing lines, you'd better ask in the plumbing forum, but I don't know why that would be a problem.

Note, with all this renovation, you probably need to bring the kitchen up to code: required small appliance circuits, GFCI protection, etc....

Hi Ronnatalie, there's a problem getting to it from below. The ceilings downstairs are a finished knotty cypress and I'd prefer they not be cut into. We are redoing the floors as part of this reno and thought we could get to things by cutting into the plywood (hard enough since there are 2layers of 1/2" plywood. Also, I was thinking that because there's a 220 line in the ceiling that was used for power tools right below the island, I was hoping it could be pulled up through the floor. And because the new wall oven is right over the panel box downstairs, it would be fairly easy to thread it through the ceiling. Am I simplifying it too much? Is it harder than it seems? And will this be expensive to carry out?
Also, you're right, there are no GFCI circuits in the kitchen. Are there different ways to install these? It seems to me I had one of these in a bathroom in another house and when it tripped I had the hardest time figuring out how to reset it. Thanks

An electrician can tell you how much of the ceiling might need to be cut up or of the wires could be pulled from other positions.

The usual way of doing GFCIs in kitchens is to use a couple of GFCI receptacles (a GFCI receptacle can protected other receptacles connected to it).

Back in the early days of the GFCI requirements, the code allowed all the places that needed GFCI protection then (bathroom, outside receptacles, etc...) to be chained together on a single GFCI which meant typically if it tripped you had to find it (typically in a bathroom somewhere).