So I'm looking at a Fighter/Druid, but would I be able to use Combat Grab while wild shaped?
"Unless otherwise noted, the battle form prevents you from casting spells, speaking, and using most manipulate actions that require hands. (If there’s doubt about whether you can use an action, the GM decides.)"
Combat Grab and Snagglilng Stike both have "Requirements You have one hand free, and your target is within reach of that hand."
What about "Requirements You are wielding two melee weapons, each in a different hand." Does unarmed attacks count as melee weapons? Or Claw + Bite count as 2?
Or knockdown assault, "You make an attack to knock a foe off balance, then follow up immediately with a sweep to topple them. Make a melee Strike. If it hits and deals damage, you can attempt an Athletics check to Trip the creature you hit."
Any of them? All of them? None of them?
IMO you can use an attack that requires a free hand if the form has some way to grab (since grapple doesn't have the Manipulate trait) that doesn't come from that very attack (so essentially is a "different hand" even though hands may not be involved). So not a rhino, but yes for a gorilla. I'd say yes for creatures like bears which have a grab attack. This is iffy ground though, so I'd stick to creatures w/ hands or a natural grab attack that you won't be using (like a snake use its bite and who has its coils "free" to grab with).
Unarmed attacks do not qualify as weapons.
Unarmed attacks can definitely be melee strikes for Knockdown Assault.
The unarmed tag, which is applied to all wildshape attacks I believe, says to use the free hand tag for grasping appendages. Free hand states that you can use both abilities that require a free hand as well as those that require you to be wielding a weapon. I assume the implication there is that unarmed attacks are considered wielded weapons, but I believe that's arguable.
So, if you have a grasping limb type unarmed attack, then you are considered both armed with a melee weapon and unarmed. There's no grasping tag though. They really aught to have given the free hand tag to grasping unarmed attacks rather than leaving it open to interpretation.
Fists and claws should be fine though, so ape, most birds, dragons, earth elemental. You have some options.
Combat Grab and Snagglilng Stike
Or knockdown assault
All three of these require a free hand, but none of them involve manipulate actions, which is why battle forms specifically block.
I think they should work. Knockdown definitely but I could see some GMs maybe getting fidgety about combat grab or snagging strike.
Does unarmed attacks count as melee weapons? Or Claw + Bite count as 2?
Page 278 of the CRB makes it clear that unarmed attacks are not weapons and nothing that works with weapons works with unarmed attacks unless it specifically calls out unarmed attacks.
"hand free" = yes.
"unarmed" = yes.
"wielding a weapon" = no.
But, I'm not sure about knockdown assault. Wild-Shape has..
"One or more unarmed melee attacks specific to the battle form you choose, which are the only attacks you can use." So you can't normally use Trip (which seems pretty silly IMO)
But would Knockdown assault let you use Trip anyways?
Do feats override spells?
Also, would Advantageous Assault give +2 damage, as wild-shape damage is 2d6? What about a snake (2d4 piercing plus 1d6 poison), would that get +3 since it has 3 dice?