The old emaxx tranny wont work with that centre diff, as its ment for the new emaxx/erevo, so that route isnt open to you.
You could modify the chassis to fit the new tranny & use the center diff if you wish, but your current tranny will be redundant.
If I were you, I'd probably use the tranny you have and live without a center diff- they are a bitch to tune properly anyway so you are better off without
As for center drive shafts, you would require a custom length due to the emaxx tranny and revo chassis- best bet would be for custom steel dogbones from Mike, made to any length once you know whats needed.