I love all of those except
Katell (sounds like a weird tryndee invention) and
Katinka (nickname, and it reminds me of "tinkle"). I also love
Kaja and
Katya as nicknames, though I prefer do
Kaia to
Kaja.
If I had to pick a favorite it'd probably be
Katarina. Pretty, classy, and versatile. It's one of my favorite names and I'd seriously consider using it with
Kaia as the nickname. If I moved to Poland or the Netherlands I'd use
Katarzyna or
Katelijn, respectively. They're beautiful but would be disasters in English. And of course,
Katharine is always an excellent choice. I like this spelling in theory but in practice I'd go with
Katherine for simplicity's sake.