When you say "keep model costs down", do you mean dollar cost or points cost?
Your characters are all poorly chosen. Let me explain. This guy...
HQ: Wolf Lord in Power Armour (230 pts)
1 Wolf Lord in Power Armour, 230 pts (Belt of Russ; Runic Armour; Wolftooth Necklace; Frost Axe x1; Plasma Pistol x1; Warlord; Saga of the Bear)
is not needed and has poorly chosen wargear anyway.
A wolf lord doesn't need a
WTN because he already hits just about everything on a 3+. (He has
WS 6 !) Second...Frost Axe and Plasma Pistol? Those are the two MOST overcosted wargear items in the codex. Not only that, but you have to get him into close combat in order to begin paying for himself and how many squads of firewarriors can you buy with 230 points? Answer, more than you can reasonable expect to get into
CC with.
My advice is to drop the Wolf Lord and get TWO squads of Long Fangs like this...
These are the perfect thing for laying waste to Tau, and even against most other armies will provide a threat to troops.
Next...This guy...
HQ: Wolf Guard Battle Leader in Power Armour (160 pts)
1 Wolf Guard Battle Leader in Power Armour, 160 pts (Melta Bombs; Wolftooth Necklace; Jump Pack; Bolt Pistol; Power Sword x1; Saga of the Warrior Born)
Also will not pay for himself. If you want a character to lead skyclaws, then the correct choice is a Wolf Priest.
The Priest is cheaper, just as killy and is a much better leader for the skyclaws.
Finally, your Rune Priest...
HQ: Rune Priest in Terminator Armour (190 pts)
1 Rune Priest in Terminator Armour, 190 pts (Chooser of the Slain; Wolftooth Necklace; Master of Runes; Codex Psychic Powers; Jaws of the World Wolf; Murderous Hurricane)
isn't too bad, but you've spent so much on wargear that you might as well just get another priest. My suggestion is to take 20 points from what you've saved on your wolf lord and do this instead...
Now one of these dudes can hang out with your infantry and move forward while the other one can hang back (preferably with Long Fangs) and cast divination.
Last but not least. You don't need two squads of Sky Claws, but you DO need something that can deal with armor and/or Flyers. Ditch this last squad and get a third unit of Long fangs with Missile Launchers.