You could try rewriting the wolverine to reflect what they're really like...
Sorry, I (and my animal-loving friends) can't read the animal stats in the MM without making disparaging remarks about the level of natural history knowledge at WOTC.
Yes, allow barding, and also magic item use (cf the Magic Item Compendium for which slots are available for which animals) but if your players is really interested in making his animals more survivable and useful in the kinds of situations that PCs get into, you may find yourself needing some way to advance the animal other than the simplistic rules in the MM. I'm trying to work up something based off of the Noble Steeds concept, which permits PCs to donate xps to their animals and give them classes, feats, and skills (tricks). The thing I'm having most trouble with is HP advancement. If you advance a companion animal the same way you do a PC, you rapidly find yourself in situations where a kitten can go toe-to-toe with a tiger, and even by D&D standards that's pretty silly. There's also the factor that you can't expect a DM to work up classes suitable for every possible animal type ahead of need; and of course the stupid MM write-ups make all animals the same intelligence, which doesn't allow you to teach even a dog a normal number of tricks. What you need is a different scale. Animals have a different style of intelligence, more concrete and less abstract; and social animals have different capacities than solitary ones and I am in serious danger of going so far past the OP you can't even see it from here so I'll stop now.