1. Plans are for investors, to keep teams on track, or documenting wild guesses. You're not taking on investors, you're flying solo, and you don't need to document your guesses (yet).
2. Founders are great for analog load balancing and as a support system. If your wife is supportive, keep moving. If she's not supportive enough, start a local HN meetup or tap into other existing groups.
3. I can only imagine trying to budget with 4 kids that $200/mo might be hard to come by. Plead your case on kickstarter, and be sure to tell HN.
In conclusion, GO FOR IT!