If the Alleluia verses do not belong in the Byzantine practice then why do all the Greek Epistle books print them? Just because something is not done in your parish does not mean it is not part of the actual practice.
a) As far as I'm aware, they're not done in a number of eparchies of the Ecumenical Throne. They're certainly not done in the Greek Orthodox Archdiocese of Australia, I'm fairly sure they're not done in the Greek Orthodox Archdiocese of America or OMHKSEA, and while I'm not certain about Thyateira and Great Britain I don't yet have any reason to think that it would be any different (though would welcome information to the contrary).
b) The fact that something is in the books doesn't mean that it's done. The canon in the Octoechos is probably the best example of this - while some places might do the full canon (without skipping any of the troparia), few would sing it, so the tone is almost irrelevant for most places. Fr Seraphim Dedes' work doesn't include the canon, and even HTM's menaion didn't bother setting this to Byzantine meter when they translated, so the reverse can also be true.
c) Again, to answer the question properly, scamandrius would need to say which jurisdiction it's for.