The question boils to: Does "can use all standard speed powers except" equals "Can't use the exception powers"?

So if Le Fay gains stealth let's say from Nekhrun trait or by equipping the Bat cowl, would she be able to use it.
Likewise if an effect would case her to use Earthbound/Neutralized, would she?

If she gains Stealth/EB from other sources she will be able to use them. Her power doesn't say she can't use them, it just doesn't grant the use of them.

I like the question, though...it's a way of thinking about the power that I hadn't thought of. I would have assumed the answer that was given was the way it would be ruled, but it was definitely worth asking.