Supposedly the Episcopal Assmeblies' list of canonical bishops can be put to use on this.
Is there a history of Orthodoxy ever trying to reach out to these vagante groups and bring them into the fold?
In some places, there is a history of ignoring vagantes in order to avoid granting them the appearance of legitimacy through association with canonical clergy. There is wisdom in this, but it doesn't resolve the matter of their existence and the spiritual threat they pose to the innocent and unwary.
On the other hand, it can also be put to use against groups like that of Fr. Anastasios, and I have a feeling will be.
There is a major difference between these vagantes groups and the church in resistance movement. The vagantes claim Orthodoxy and try to pretend to be in communion or claim that they are kept out of communion because the legitimate Orthodox groups are just ethnic bigots. The churches in resistance are Orthodox but have chosen to separate themselves from Orthodoxy, they are very up front with what they are.
The litmus test on how close someone is to the Church is looking at what it would take to bring them into the Church.
Resistance Churches (aka Old Calendar movement) - confession, clergy received as clergy
Oriental - confession, clergy received as clergy
Roman Catholic - anointing with Chrism, some traditions receive clergy, some do not
Protestant - anoint with Chrism or baptism, no clergy reception
Vagantes - anoint with Chrism or baptism, no clergy reception
Muslim or Jew - baptism
So when a Vagante bishop is left off of the Episcopal Assembly list they will cry about being persecuted but, when a church in resistance is left off they will be happy.