so if you use your action to dash, can you still use the haste action to dash as well? and it doubles ALL speed, including a monks step of the wind?

Extra Attack
Beginning at 5th level, you can attack twice, instead
of once, whenever you take the Attack action on your
turn.

Does this mean you get two attacks from the action afforded to you, if you decide to attack for the haste action?

"to take the Attack (one weapon attack only)" which rule is followed as Extra attack specifically states you can attack twice, instead of once...

Quote from Stinkingyeti >>

I read that this lets you sneak attack again with the extra attack on a forum, but i can't see where or why it would let you do that.

 You use your regular action to hold the attack action, then you attack with your normal action. Sneak attack is once per turn, not once per YOUR turn.

You can do a combination of two levels in Fighter with eight levels in Paladin and take at first level spell Shield of Faith and Haste and you can have it 21 armor class

it says cast on a willing creature, so they wouldnt be willing to be stunned and not take it.

Quote from Sparktic >>

Extra Attack
Beginning at 5th level, you can attack twice, instead
of once, whenever you take the Attack action on your
turn.

Does this mean you get two attacks from the action afforded to you, if you decide to attack for the haste action?

"to take the Attack (one weapon attack only)" which rule is followed as Extra attack specifically states you can attack twice, instead of once...

 but the spell, which you quoted says (ONE weapon attack only).  The spell doesnt say you get an extra Attack ACTION, just one extra weapon attack.

Ah but what you can do is ready action for a point at which you can do something action on somebody else's turn. Then use the haste action to sneak attack 1 attack on your turn. Then use the ready action (say after Mike's turn) take the attack action (all your extra attacks and everything including Sneak attack)

2 Sneak attacks in one round. Also then use a reaction on enemies turn if you can force a trigger get a third Sneak attack on 1 round.

Quote from Dogpire2 >>

Ah but what you can do is ready action for a point at which you can do something action on somebody else's turn. Then use the haste action to sneak attack 1 attack on your turn. Then use the ready action (say after Mike's turn) take the attack action (all your extra attacks and everything including Sneak attack)

2 Sneak attacks in one round. Also then use a reaction on enemies turn if you can force a trigger get a third Sneak attack on 1 round.

 

Readying an action uses your Reaction to actually execute the readied action, though. You'd still only have two sneak attacks per round unless you can find a way to make an attack on someone else's turn without using your Reaction, which is pretty rare.

Hasted Scout Rogues can triple Sneak Attack in one round.

It's probably because sneak attack can activate once a turn, so if you hold your hasted attack you can attack on someone else's turn, so rules as written it would be another sneak attack 

Quote from RealBriGang >>

I just wish I could use it on multiple targets at a higher level.

Also, when it says "Attack (one weapon attack only)" is it saying that you can only use one attack action, however many multiple-attacks it is but not an extra off-hand attack? Or only that you get a single slash or stabbing or bludgeoning?

 this means that if you are hasted and have the multiatack feature then you cant use the haste action to make 2 attacks from your extra attack, you can make one attack only.

It looks like this was broken with the implementation of the new ruleset. It says [Tooltip Not Found] for what used to be Use An Object interaction. 

as a rogue you use the extra attack granted here to make an attack, then you use your action to ready an action. the action is to attack, you ready it to go off triggered by the start of the turn of the next person in initiative order. This means at the cost of your reaction you can make two attacks (because you can with haste) one in your turn and one in the next turn. As you so rightly say you get one sneak attack per turn, however you get two per round this way. 

''Use an Object action.'' text is missing

This sucks now. One weapon attack. Bullshit. I'm just at the table dealing with this now, so I just a little bitter.

[Tooltip Not Found] goes hard

Quote from GripFist >>

[Tooltip Not Found] goes hard

 
I cast [Tooltip Not Found] . . . !!

No, you can never cast two leveled spells in a single turn.

Initiative is not a saving throw, but a Dex check rather. Though i would rule this as doable on my table, it's a third level spell after all

I would rule as another attack that the form can make. Example:

Grizzly Bear: Multiattack- one bite and one claw attack.

As a wildshaped druid you would make either a bite or a claw attack, since it's a single attack.