Thanks for info eewizard, your answer was exactly what I was looking for, I purchased a Weller WES51 iron before I even stared this project, I was advised it might make things easier in the long run. You are correct I am in the infancy of this project, with much more info to collect.
Here is a little background.
It will be a 2 peice "laser tag" kind of game, with a stationary target, I know people who play paintball, I don't actually play. The board will be a in a big RPG style "launcher" I will make out of PVC that will fire a small Laser LED to the target, with the FPGA controlling how often it can be fired how many times over a length of time, they can make it parts of the paintball games they play. An advanced version may roughly measure distance with a GPS chip
My idea is the FPGA will activate Optical relays driving the 12v lights and siren for noise for a breif moment directly from the battery, the regulators will make my lower voltages to drive just the FPGA from the same 12v battery source. A similar system on the "target" with a Laser detector (unknown type) will make noise and lights if a hit is made.
Plan B is to isolate the FPGA by running it off a second power source, like a cell phone battery, using the relays to drive the lights and siren off the first 12v source.
This is a fun/game/hobby project for me, I have no deadline, no boss, just fun.
I've been through the WEBENCH process and found it helpful, Ive invested enough hours in pcb123 to stick with it for now.