Does OS X 10.12.4 include APFS?

Yes, but at this stage, a beta file system, that is not enabled by default. I would not recommend the use of APFS on a production Mac, while still in this beta classification.

Yes. 10.12.4 as HFS+ on Boot Drive. APFS as this point, in its beta state, does not support boot drives, but will when out of beta.

Good write-up here: Testing out snapshots in Apple’s next-generation APFS file system

it is out of beta for iOS but not for macOS X ?

It is not out of beta for macOS Sierra in the most recent (10.12.4) App Store release.