You could definitely go the way you have said in your original post. GFI's are mandatory as safety should always be first.
I would argue though that it wouldn't make much of a price difference to do it right for at least your boil kettle. You don't have to use a PID controller, SSR and heatsink to use an electric rig, but it will certainly simplify brewing and produce more consistent results.
I would at the minimum set up the heatsticks to come out of a box that you can have basic switches on. Pulling plugs in and out will be a pain in the ass and possibly even dangerous when you are talking about 220. Plus you would be dealing with cords all over. For your 220 you will need a special switch to handle the amp load. I have a dual pole 220/240 30amp switch as a safety cut off to my 5500 watt low density element. The switch is mounted between the pid/ssr and the actual element. It is great for me because simply switching a switch off is faster than dialing down my PID to 0% output-especially if you are on the verge of a boilover. Your local home improvement shop will most likely not have what you are looking for. I went to an electrical contractor warehouse that is open to the public to find what I need, something like this:
Expensive yes, but worth it to me for safety. Make sure you use proper wireing too when building any electric rig. For the 2000 watt elements at 120v I went with 12/3 wire. You will be drawing around 17 amps, so you 15 amp breakers won't handle the power, you will need 20 amp circuits (separate for each heat stick). Your 220 will need to have a 30 amp circut for a 5500 watt element like the one I have.
Take your time with the build, look at others rigs who have succeeded with electric brewing and don't be afraid to ask questions.
On a side note, if you do decide to go with a PID, it really doesn't cost that much more than what you are already planning-figure about 150 for PID controller, SSR, Heatsink, wireing and a suitable box. I got my stuff from Auber and couldn't have been happier. PM me or let me know if you have questions and good luck with your build.