does shady spectacles make a unit mighty if it was attached to a non mighty unit copying a mighty unit? can i exhaust fiora to channel a rune?

Yes — it becomes Mighty.

Shady Spectacles' copy effect replaces the equipped unit's copyable traits, including its Might (Rule 477.1; FAQ on copy effects confirms Might is copied). "Mighty" isn't a status or trait — it's defined purely by current Might being 5 or greater (Rules 706–710). So if you copy a unit whose Might is 5+, your equipped unit's Might is set to that value and it is Mighty for as long as the Spectacles stay attached.

Two caveats: only the printed Might is copied — gear, buffs, or Empowered status on the target don't add to it (FAQ #12291). And the copy's own attached gear (including Shady Spectacles itself) still applies its Might bonus on top, which can push it further above 5. If the Spectacles get detached, the copy ends and the unit returns to its original printed Might.

I noticed multiple unrelated questions. I've answered the first one — please ask the others in separate messages so I can give each one proper attention.