A uBEC should do the job. On www.koolflightsystems.com they say its rated for 8-10 servos, 3A continuous and 5A for 5minutes. Those little fans won't draw more than about 0.2A each, so you should be fine with the uBEC
I'd be worried about using Lipo for an RX pack. If the pack drops below 6v (2s Lipo), then you could be screwed, as in the vehicle could have melted plastic.
SH Z-Car, Custom Crawler, 8s Savage, 12s XTM XLB 1/7 buggy, 4wd 4-link rear/IFS Pro4 truck, Custom Hyper 10 Short Course, Belt-Drive Mammoth ST 1/8 truggy, 4s 17.5 MM Pro HPI Blitz