I have some questions...

[Elrohir]

Gorgoroth Breaker:
I may exert him, and then stack him to make the fellowship archery total -4, right? I am sure about this, but my brother does not agree... I hope your responds will convince him.

Glorfindel, RiW:
May I reveal the top card, even if Glorfindel is not assigned to a skirmish? May I exert him, to make a nazgul strength -x, even if this is not during their skirmish (after resolving the current skirmish, the nazgul gets his original strength back - that is clear ...)

Massing strength:
May I discard an orc, who is skirmishing, to give the (only) other orc the strength bonus? The thing is: Skirmish events just last for the current skirmish.

[Gil-Estel]

First 1: yes you can. It is a special ability, so as long as you can pay the cost, you can. So when you have exerted the dude, the only option is to stack him. Which is nice...

Second 1: you can reveal the top card, but when it is not during his skirmish, he is not skirmishing, only assigned. But it is a way to look at the top card

Third 1: so no....only for the one he is skirmishing...

[Elrohir]

Exactly what I thought -