Chinook helicopter question

Perhaps a dumb question, but if an engine failed on a Chinook would
appox only half of the power be available to continue spinning the
rotor blades?
Does a Chinook operate both of it's engines in a similar fashion,
meaning does the pilot keep both engines at the same power setting?
What would be the purpose or advantage of engine ops with different
power settings on the engines? What is a Chinook's performance like on
a single engine?

Is IFR training or flying (like approaches) in a helicopter made easy
by the fact that if you are having trouble with something you can just
stop the thing, hover, think about what you are doing and then
continue? Do helicopters have lower IFR minimums than fixed-wing a/c?
What is spatial disorientation like while IFR in a chopper and what
additional instruments are in choppers for situational awareness while
in the soup?

I watched Bush's departure from TSTC this a.m. and it was the first
time I've seen a Chinook involved with the president's comings &
goings out here. Watching this amazing aircraft takeoff & land has all
kinds of questions pulsating through my mind.
I searched online a bit but my wonderings seem a bit beyond what I
found on the internet.

Thanks,

Ricky