Some questions.

[Monolith]

Can be used a stunt to permit to that character to damage and weaken the stamina of her target in the same round?

Technically, no. For 2 different attack effects to work together they need to be purchased with the linked extra. If you bought the bracers as linked to strength they would always work every time the strength was used, and you could never use the strength without using the weaken while wearing the bracers. Without linked they're 2 different attacks that require 2 different standard actions.

A gm might allow you to use a hero point and get a 1-round link. That would be up to them.

a.) If yes, the target must first roll against weaken or damage?

The player and gm get to determine which goes first, so yes, the weaken could go first.

2) Can be used maneuvers live power attack with attacks like weaken bracelets?

All attacks can use any of the maneuvers.

3) Can a character have a type of teleport limited only to a plane of existence? Like teleport limited to Asgard, for example. How much costs?

Yeah. You build it with the movement (dimensional) effect.

[Alex_UNLIMITED]

2) Even with affliction?
New question:
1) A character today says: "I become insubstantial, then I attack Superman Cyborg by entering my arm in him, and then I remove insubstantial to hurts he."
It's possibile? How?

[Arthur Eld]

2) Yes, even with Affliction.

1) You have to buy as a separate power, unless the GM wants to rule it a circumstance bonus to regular unarmed damage.

Note that it doesn't have to be damage, the official Phantom Girl build has an Affliction (Resisted by Fort, with Dazed/Stunned/Incapacitated as the conditions) power to represent her Phantom hand effect.

[Monolith]

2) Even with affliction?

Any effect that requires an attack check is an attack and can use a maneuver. It doesn't matter if it's a punch, webshooters, strength-draining gas, or anything else. It it requires an attack roll you can use a maneuver.

New question:
1) A character today says: "I become insubstantial, then I attack Superman Cyborg by entering my arm in him, and then I remove insubstantial to hurts he."
It's possibile? How?

It's important to decide what effect you're trying to do. The descriptor could be something as simple as a penetrating advantage on your strength to represent sticking your arm inside of someone that's hard to hurt or it could be a separate attack like an affliction, as Arthur mentioned. Don't confuse the appearance of how it looks with the effect of what it does.