No Catholic Priest needs conduct any marriage ceremony other than the Sacrament of Marriage. There is no requirement for a priest to be a Registrar.
In England at least, any Catholic parent can set up a Catholic school for Catholic children. It would be nice if the Bishops were on board but if they persist in CESness, then the only thing the parents have to avoid is the word "Catholic" in the school's name. "One Holy Roman and Apostolic", on the other hand, appears not to be at issue. (You get the same state contribution to the school as the diocesan school does.) Where is our Church's Toby Young?
Nobody has to attend Mass in their own Parish if the celebration of the Liturgy is enough to be (for them) an occasion of sin. Your obligation is to support your priest. Five decades is good support. £10 might encourage him in contumacy.