Here's some more information I translated from here: http://www.konami.jp/products/nura_ps3/info.html
I only translated information relevant to the battle system.
During battles in Nurarihyon no Mago Hyakki Ryouran Taisen, in addition to the Supreme Commander you are controlling, you take your aides and minions and form one team to do battle.
During battle directing your aides and the timing of summoning your minions are vital tactics and utilizing these components are essential to how battles unfold.
Because each character has different abilities and characteristics, you’ll be able to develop many different strategies depending on how you construct your team.
Experiment with all of the combinations and create the strongest team!
Combine your power with your companions and claim victory!
As you defeat your opponents, the Influence Gauge at the bottom of the screen increases. Once your team’s side of the gauge fills up, victory is yours!
The player controlled character acts as the main character. In addition to issuing attack and defense commands to the aides, you can also summon minions.
Aides – Command-able
During “Guard Mode”, the aides automatically take action to protect the Supreme Commander, while in “Attack Mode” they focus on attacking the enemy. The aides can automatically switch between these two modes, but the player can also command them directly.
Minions – Summon-able
During battle you can summon them and they appear for a fixed time to battle. You can set up a formation of up to 8 minions.
“Shima” and Fear Gauge
Breaking Shima will give you benefits during battle
Throughout the stages are stones called “Shima” placed around and breaking them gives a fixed amount of damage to your team. (This is worded strangely, but I think it’s saying breaking these will allow you to heal.)
Reclaim taken Shima!
As the number of Shima increases, you will be able to summon powerful minions!
Build up your Feat Gauge to unleash a powerful strike!
By attacking the enemy and claiming Shima, your Fear Gauge increases.
Build up your gauge to unleash your ultimate technique or your Hyakki Yakou Technique to finish the battle in an instant!
With 50% of the gauge you can unleash your ultimate technique!
With 100% of the gauge you can invoke your Hyakki Yakou Technique!
A note about the “Shima”: Shima can mean “territory”, which in the context of this series would make sense if that’s how they mean it here. The stones here are referred to as “Shima” as if they are a proper noun, so I didn’t translate it. Essentially you destroy the Shima to control the territory around them. It’s probably best to think of them “Territory Stones.”
Another note: If you’re familiar with the series you’ll know that “Hyakki Yakou” refers to the Commander’s “Night Parade of 100 Demons.”
Also, there's been an update to one of the game pages. You can take a look at a lot of the support characters and their abilities: http://www.konami.jp/products/nura_ps3/chara02.html
That information in addition to closely examining the trailer you can see that all of the Shikoku Yokai that have every participated in battle will be supports, except we haven't seen Tamazuki so I think he'll be playable. Everyone from Touno who has attacked will make an appearance too as well as the Onmyouji.
I just took another close look at the trailer and I noticed a support card for Kidoumaru, which could mean a couple of things. It could mean that there will be support cards for playable characters too and if that's the case, just because we've seen support cards for some characters that doesn't exclude them from being playable. Or it could mean the card is for the past version of Kidoumaru, in which case being a support probably excludes you from being playable.
In terms of remaining playable characters I'm only expecting past Nurarihyon and Tamazuki. I'd guess that Seimei will be a support character.