It's entirely possible to believe Jesus as Messiah and Savior and proclaim oneself to be "Judean/Judaic."
The Apostles, did they not believe Jesus was their Messiah and Savior yet proclaimed themselves to be Jewish. See Acts, chapter 2, starting at verse 14 where Peter says to the people "fellow Jews...." I take that to mean that Peter and the brethren with him were Jews yet they all believed Jesus to be Lord and Savior. "There is no other name under heaven by which we must be saved."
Paul believed Jesus to be Messiah and Savior, yet proclaimed himself Jewish. "circumcised on the eighth day, of the people of Israel, of the tribe of Benjamin, a Hebrew of Hebrews; in regard to the law, a Pharisee" Phil 3:5
"for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek." Romans 1:16