Do GApps 4.4.4 work on Cyanogenmod 11 with 4.4.2?
To answer your first question, yes. 
May I recommend ParanoidAndroid GApps for a reliable source of current GApps.

To your second question: make sure you do a wipe BEFORE you install your system rom and gapps.  

Sidenote, its quite possible there are outstanding bugs in your rom. For this reason I highly recommend following guides on Xda Developers