You're really asking two unrelated things here:
1) How do we access money in our 401(k) before age 59.5 without paying penalties?
2) How do we use our investment portfolio to pay for things?
For #1, see
http://www.mrmoneymustache.com/2011/11/11/how-much-is-too-much-in-your-401k/ for options. A Roth conversion will be taxed as ordinary income, as will SEPP.
For #2, use
a total return approach (pdf). To "generate income", take whatever dividends/interest your portfolio naturally produces, and then simply sell shares after that until you've fulfilled your cash needs. No special focus on dividends or bond interest is necessary (and in fact, it can be suboptimal). The idea of generating income solely from dividends is a bit of a historical relic, from when dividend rates just happened to be high enough to produce sufficient income, and when the high transaction costs to sell shares made dividends a more efficient option. Both of those situations are no longer true.
During #1, whether you do Roth conversions or SEPP, that money will be taxed as ordinary income (at your new lower tax rate). For #2, dividends/interest will be taxed as dividends/interest, and sold shares will be taxed as capital gains.