This is precisely why I would put you in between. You don't believe in the replacement aspect and do look at the feasts (at least familiarized yourself). But there are also some Christian aspects that you agree with as well (ie Sunday).
There is no in-between. She is either trying to be a practicing Jew or not.
Messianic Jews are, apparently, genetic* Jews, practicing Jews, but not believing Jews, because their faith is Christianity.
Christian Jews are genetic Jews, but not practicing or believing Jews.
As far as I know and if the line is through mothers, KFC is a "Christian Jew", i.e. a "Christian", where her Jewish nationality has no influence in her faith or practices. But she is not a "replacement" Christian who believes that G-d has abandoned genetic/practicing/believing Jews.
Jesus himself was, if he believed what later Christians said about him, a Messianic Jew, since he was a genetic and practicing Jew, but not a believing Jew any more. (Until he decided that he was the Messiah and/or son of G-d, he was also a believing Jew.)
(*"genetic" includes converts and Jewish descendants of converts)
I'll post an article soon with a table that differentiates between the Jewish people (Hebrew-speaking people from Canaan and their descendants and accepted), the Jewish religion (set of laws and rituals), and the Jewish faith (set of beliefs), and will also include Muslims and Zoroastrians plus a few different Christian sects if I can figure out the differences between Eastern Orthodox and Oriental Orthodox in time.
(And the Ethiopian emperor will take the cake: He was a Christian, a descendant of King Salomon, not a Jew, and the Rastafarians think he was Jesus reborn and G-d personified which he himself disagreed with.)
I think the whole thing can be sorted according to prayer day:
Friday: Muhammed's followers, since Friday Jews and Christians could come and listen
Saturday: Jews, since Saturday is the 7th day
Sunday: Christians, since Sunday is the 1st day, except some sects that embrace Saturday instead
Messianic Jews follow a Saturday religion.
You can even sort countries according to their weekend definitions:
Thursday-Friday: Islamic countries with little or no Jewish influence
Friday-Saturday: Islamic and Jewish countries with both cultures present at some point
Saturday-Sunday: western (mostly Christian and Jewish influence) and secular (Turkey)
Friday only: Iran
Sunday only: old-style western (Christian influence only)