Ari64's branch of Mupen64plus is the most suitable N64 emulator to start a port with, on account of having a fast ARM dynarec that does optionally target ARMv5 and works w/o hardware FPU support. With anything else you'd have to go with an interpreter which would be dog slow.
But no matter what you choose to port you run into the same problem, a lack of GPU code, because there's no plugin targeting OpenGL ES 1.x and for that matter little actually supporting any OpenGL at all. The closest you can get is glN64 which targets OpenGL 2 and was ported to OpenGL ES 2 for use on Pandora. When I looked at it I believe there was some support for the OGL 1 style fixed function pipeline so OGL ES 1 support might not be a distant target. But the support there is not really even close to sufficient for getting N64's fragment operations down (particularly its combiner). If you hit Wiz/Caanoo hardware more directly you'd get a closer approximation, and with less driver overhead which could really be costing anything.