I like to look up the meaning behind names and use several websites that do that and try to match it to the characters but sometimes a name just jumps out at me. Like Ynyr, I just really liked it and it is associated with 'honor' and that fit perfectly.
Grim and yes, I made a conscious decision to not spell it the common way, because Grim isn't a common guy. It just needed to be his name, I can't tell you why and it took forever for my computer to stop trying to change it.
Others like Oryon and Isis I pulled from mythology.
Isis was the most powerful of all the female Goddesses in ancient Egypt and I wanted that for the character even though others don't see her that way. She was strong for the stand she took on not leaving Oryon.
Oryon, of course, is a different spelling for Orion from Greek mythology who was a mighty hunter. I liked that and made him the Lord of the 'Hunt' planet that I called Betelguese because Orion is also a constellation, and Betelguese is one of the brightest stars in that constellation. Rigel is the other one so therefore he became Lord Oryon Rigel of House Rigel on the planet Betelguese.