What are the minimum specs requirements (processor speed, RAM, etc) to run a CSE ROM?
Not quite sure, I don't have access to a lot of hardware to really get a good feel for it. Right now the worst phone I have is an Inspire 4g (1 ghz, 768 MB ram), and I've managed to get 84PCSE usable on it. Its definitely got some lag to it, but it never maxes out its frame skips, which means the core is still running in real time, even if the display is dropping frames. On an S3 it runs pretty smoothly, no major frame drops.
I've made some major performance improvements, that have a pretty noticeable impact under normal operation for lower end devices.
If you want to be testing the latest features, I've added a beta build to the app store. You can opt-in by joining the group:
https://groups.google.com/forum/#!forum/wabbitemu-beta, and then following this
link. Once you select 'Become a tester' you'll then automatically receive beta updates for Wabbit.