Yes, obviously Fr Michael is not vested and is not concelebrating. Nice to see he seems to be in traditional Roman Rite/Anglo-Catholic gear, cassock and mozetta (shoulder cape that an Anglo-Catholic rector wears). I can understand a last Mass before converting but so doing when no longer under a bishop doesn't make much sense (though valid in Western sensibilities).
The CEC were a recent success story in new denominations, a church of about 15 years' standing of Pentecostals who read the church fathers and in moving catholicwards became do-it-yourself anglicans (they were never Anglicans/Episcopalians) picking up vagante
orders from a Brazilian church's bishops along the way. Not an imaginary church: real churches and congregations. But they imploded recently: sex scandals with some of the bishops and they didn't quite get how the episcopal thing is supposed to work so they freaked out about it like Pentecostals and split up.
Unlike a former Roman Catholic or Eastern Rite Catholic priest, like an Anglican Fr Sergio will be treated like a layman until he's ordained Orthodox.
Although they weren't Anglican really I can imagine St Clement's doing what the ex-Anglican majority in the AWRV do and use 'St Tikhon', the still ad-hoc modified American Missal
(itself a modified US 1928 Book of Common Prayer Communion service - the Orthodox version has no filioque
and a stronger epiclesis and is clearer about the sacrifice and change of the elements) and 1928 BCP offices of Morning and Evening Prayer. (More or less what a high-Episcopal parish did around 1960 and what 'Continuing' breakway American ex-Episcopalians who left in the 1970s use. It looks a lot like the Tridentine Mass but sounds very different: the texts are different.)
A complete though unofficial AWRV BCP with the American Missal-based Mass is in the final stages before printing.