Last I checked the Z97 series was made specifically for Devil's Canyon. I don't see why it wouldn't come stock compatible with the i5-4690K.
And no you can't flash the BIOS via USB if the mobo is not compatible with the CPU in the first place (you won't even be able to get into BIOS).
Do you really care about the look of your mobo? Because if you don't you can save quite a bit of money and get the Gigabyte Z97X-SLI which is currently the best-bang-for-your-buck Devil's Canyon mobo. It can be had for as cheap as $99.99
It comes with SLI capability, SataExpress, SataM.2, ability to overclock to 4.7Ghz, and a Realtek ALC1150 high-end audio codec the same one found on the Gaming 5.
Though the Gaming 5 does look better, practical-wise they'll produce identical results.