I think Battle Defense would be a waste, too many of it's abilities do nothing useful, wondering if you meant Feint for halving damage?
I think the idea of using two pets with this build is not a great idea personally. It's a busy template to play just fighting alongside the pet. Depending on what you're fighting obviously. I'm going to posit at a Champ Spawn for example, these are not high level by any stretch of the imagination but with varying levels are a good test of player skill, if you can't handle a spawn you're probably not ready for the next logical progression (Peerless? maybe)...
So two versions of this:
1. 2x defensive pets with less damage output plus you the player as a dexxer.
and
2. 1x 5 slot pet, like a Hiryu, Rune Beetle, GD, Fire Beetle, Triton, plus you the player as a dexxer.
With 1 your pets take longer to kill things, which means they take more damage, and they go off in separate directions and get stuck. Your ability for healnig them is limited to Chivalry or Vet which require close proximity and you can't be in two places at once. Two of the best functions of this template are that you can go be 'warrioring' at the same time as your pet fighting, in a spawn with two of everything (and assuming you're 4/6 as originally intended) you'll be switching in and out of EoO for every target and using your Chivalry to RC on you and pets, and possibly Cure them if they're fighting RC's. The other best function is to use pets as actual shields, standing underneath them while they take all the incoming until everything's nicely gathered up to WW/Hit Area/Guard. With weaker pets, and if two are getting hit at once, you may struggle to keep up with their Vetting.
With 2 by comparison you can leave your tankier pet knowing it's not going to die without constant attention, you can easily shield under it for WW'ing at level ups, and as you're not spending as much time looking after it you're more able to play the dexxer part of your template. On the final Champ it's much easier to set it up fighting one pet than two if you need to get it on the same tile to avoid re-targeting (Semidar for example).
If I were using lesser pets I'd probably prefer to tank with my player, in which case I may as well use 5 Frenzied and glass cannon it.