The Android that phone builders download and customise is based on Alsa in the kernel - but Android doesn't define access to ALSA in any way (and the phone manufacturers could use something completely different.)
The audio "layers" (and it really is that) are quite complex, with OpenSL along with the defined Java sound APIs as the only userspace methods to play sound.
Unfortunately due to the way the layers are defined (multiple mixers for various devices, incoming call interrupt etc) it's not "Alsa" available in userspace and you can't rely on that being there.
So to answer your question:
(yes) Jack could be compiled on Android - but the use of Alsa is not necessarily reliable and/or available on all devices.
(no) Using native Alsa might not solve the audio latency problems - since that's a function of audio buffer size and throughput.
Don't ask me why, but Google define 45ms as low latency....... Meanwhile, in Apple Land, both the iPhone and iPad are happily realtime audio scheduling around 4-5ms...