I actually like the standard Wolf as an animal companion, even with the whole Druid list available. Having a single primary natural attack combines well with high Strength & Power Attack. Also, as a Hunter you can benefit from single powerful attacks by exploiting Broken Wing Gambit & Paired Opportunists.
Tigers are a very good option though, with pounce and multiple attacks being great.
I'm sorry for your loss. I know that animal companions are sometimes even better than regular companions, I mean I'm sure he only took that critical in an effort to protect you not because you were placing the animal in danger.
Take the proper time to mourn, then take a solid day to pray and nature will provide with a new companion.
Narrow Frame is a solid feat for any animal companion which will become large at level 7 - it makes it easier to deal with narrow corridors and doors.
Power Attack is usually a good choice with a single natural attack AC like the wolf. You get +3 damage for every -1 to hit, same as using a 2-handed weapon. Combined with Improved Natural Attack you can make some big hits.
Light Armor Proficiency is a trap - as Flutter says, masterwork studded leather or a mithril chain barding has 0 Armor Check Penalty and can be used without penalty.
Getting an Intelligence advancement at level 4 means you can pick any feat you qualify for, opening up a ton of options.
As I mentioned earlier - Broken Wing Gambit and Paired Opportunists are great feats, but you only need to take them on your hunter due to Hunter Tactics - Having Combat Reflexes is a nice bonus too. Outflank and Pack Flanking are another great combo. If you're the sneaky one in the party consider Stealth Synergy to reduce the risk of bad rolls.