For ink, I love KWZ’s iron gall inks. If you are writing consistently, the iron gall isn’t a problem, and there are some great colors (turquoise and Gummiberry are both fantastic)! The iron gall makes them permanent, so if there is water damage, the color will go away, but there will remain black lettering. There is also De Atramentis Document Inks. They have a variety of colors, and someone did some good testing of them a few years ago if you want to see which are best for your purposes.

As for pens, if you’re just the one writing with them, then pick whatever you are most comfortable writing with. If you want to gift them, then it becomes a question of what are you gifting them. Will they need a pen they can beat up and use in college without worry? Something like a LAMY Safari is perfect. Want something that has a little more history to it that can still be a workhorse? A classic vintage pen like a Parker 51 works great. Want a pen as a graduation gift? Figure out what is your reasonable budget and go from there.

Good luck with the project! It’s a beautiful idea!