If I was doing it the first time I would opt for A 123 batteries for the receiver/servo electrics. One 2,500 mAh battery will fly it with tremendous amounts of amperage for roughly 6 or 8 flights before needing a recharge. Depending on where you go for the battery you can obtain the switches already adapted for the battery type, eliminating any need for plug changes. They can be recharged at the field in about 15 minutes. No reguators are needed. Battery technology keeps moving forward and for the last year or so the A 12 batteries have been leaders of the pack for power, amperage, reliability, and simplicity. Wild Hare RC and Sin City jets is where I would go for the battery, with Wild Hare being my preference.

For the ignition you can generally use a simple 4.8v AA cell nicd or nimh of about 1,000 mAh.

A power distribution is absolutely uneccessary. For the application it's a waste of money and weight. For a much larger plane they can be beneficial, so if you elected to buy one obtain one sized to deal with a much larger plane.

Ignition kill is a personal thing. In all the gassers I've built and flown I've never used or needed one other than what's avilable with the transmitter with the throttle stick and idle trim but there are some that won't get out of bed without one.