What is the tradition/custom when praying for or having a Mass said on behalf of someone we have a strong inclination is a saint, but who has not yet been formally canonized by the Church?
For instance +Abp. Lefebvre. Should one say “pray for us” or “requiescat in pace”?
Are Masses offered for the +Abp and/or his mother for the cause of their canonization or for the repose of their souls?
The Church's history has many instances of the Faithful having been moved by zeal to recognize someone's sanctity.
Normally now, it is up to the Church to officially recognize and to canonize a saint, but see what we have happening, the so-called canonization of John Paul II and now, if that wasn't quite sufficient, this October we have the looming specter of the same nonsense but this time for the infamous Paul VI. Fr. Luigi Villa did his best to warn us but his best might not have been sufficient, somehow.
When St. Anthony of Padua died, the Catholics all over Italy raised their voices and came from far away to the place his body was kept. There was such a spontaneous eruption of demand for his sainthood that the Church recognized him as a saint only one year later. The Catholics of his home town, Lisbon, Portugal, still refer to him as Saint Anthony of Lisbon, after nearly 800 years (will be in 2031).
Nobody could convince the spiritual children of Padre Pio that he wasn't a saint. I know some who started praying TO him as soon as they heard he had died. They didn't wait for Rome to speak.
And today, when they say Rome is speaking, it somehow doesn't sound like the voice of Rome we recognize.
So you have a number of things to consider here.