Some new bugs:
You can grab while holding an item. Is this intentional?
When holding an item and using a Final Smash that transforms/takes your character off-screen you lose the item you're holding. I checked with Snake and Fox only, not with characters such as Sonic, Tails or Megaman.
Also, a glitch that's probably very hard to reproduce: I was playing as Fox and toyed around with the Shine close to the right ledge on Asteroid Fields. Now, I don't know what happened exactly, but I grabbed the ledge, tried to go up and was pushed back to the ledge again, Fox tried to go up but was pushed back, and so on. I couldn't control the character, was invincible the whole time, and didn't occupy the ledge (my opponent could grab the ledge without problems).
Edit: Items disappear if you hold them while off-screen. Also, holding an item as Samus/ZSS and using your FS causes the item to become "attached" to your body, but you can't use it. It disappears from your character when you're off-screen.