Congrats! I am very happy that you may have gotten the desired servant! So enjoy playing as him!

Congrats! Use him well. Simply lovely rolls. Grande lavoro. Just leveling them all. You can take consideration whether you have the items to take them to final Ascension. But ultimately, everyone should be leveled up.

Grail the smoldusa.

Karna's still pretty solid. Different niche though.

Ana is more a focused Archer obliterator.

I really like Karna a lot in terms of his character and design. Unfortunately, in global, his battery is still 25% which practically speaking is a mere 20% battery. Unless you level his battery append some (or all) and give him a 50<% starting charge CE, he'll not NP on turn 1 on his own steam (unless a Kaleidoscope is involved). Given that you have Skadi, I think giving Ana priority is the obvious choice at this point.