On the contrary, the Easter Vigil water should always be used in the EF, unless it’s not available. During the Easter Season, it must be used. Outside the Easter Season, it must first be blessed by a priest.
To keep things simple, I would strongly suggest obtaining some of the Easter Vigil water
now, while it’s still available, and setting it aside.
Follow the 1962 Roman Ritual exactly as printed. No variations.
These are the rules
sanctamissa.org/en/resources/books-1962/rituale-romanum/07-the-sacrament-of-baptism-general-rules.html
This is the rite itself
sanctamissa.org/en/resources/books-1962/rituale-romanum/09-baptism-of-children.html
Whether the source is a physical book or an online version, they will be the same.
Of course, the deacon needs the permission of the proper pastor of the place.
I don’t think it’s a matter of trusting or not trusting. I wouldn’t expect the average priest or deacon to know this offhand anyway, unless he’s already familiar with the Extraordinary Form.
Good. That much is a given, no matter what else. Whether he uses the Extraordinary or Ordinary form, no cleric may baptize in any church without the pastor’s permission (except in danger of death).
**I know that this thread has become rather complicated. The solution though is very simple. Just make sure he has the Roman Ritual from 1962 (online or physical) and as long as he follows that exactly, there won’t be any issues.
**
Remember to have some salt blessed by a priest because that’s an important element in the EF Rite of Baptism.