Your questions in order:
1) CM11 had a "turn on tap and pay", setting. It did nothing. I frankly forgot to check of Liquid Smooth had it. It was a VERY nice 4.4.4 AOSP rom. For sure, Google Wallet tap and pay was not only not working, it was not even available. There was no NFC logo that appeared.
2) yes, I've only ever installed GW from the play store. And what I finally found out when I got tap and pay working on the stock unrooted att 4.4.2 rom was that Google wallet did not even offer the option to set up tap and pay in the 4.4.4 aosp roms. In fact, it was not even showing as grayed out. It was not even mentioned at all. If you were not a savvy smart phone type, you'd never even know gw ever offered tap amd pay or that such a thing even existed. But now with this new stock rom, it just shows up in gw and was easy peasy to configure.
Thanks for pitching in. It has partly renewed my faith in xda. Googljng outside xda I have seen slivers of evidence that aosp roms need patches to do hce, or at least the 4.3 ones do.