Ferocious Roar + Ancestral Cry | How does this interaction works?

Hi!

My question is simple yet complex...
Can anyone help me explaining how interaction between Ferocious Roar + Ancestral Cry works?

Scecifically:
1) Ferocious Roar is not an attack. Does it allow to support Ancestral Cry with gems that related specifically to Ancestral Cry ?
(You can set the gems into Ferocious Roar and some are clearly works. It is unclear if gems like Close combat will work.)

2) Ancestral Cry clearly receives increased damage from Ferocious Roar. How should this damage be considered?

-- My build is already 100% fire damage. It means that there is almost no benefit from provided damage conversion. (less than 5%)

-- Ancestral Cry make all attacks Ancestrally boosted, thus they make 30% more damage.

I made some testing... It is not entirely clear (and incorrect probably) but damage output through Ferocious Roar + Ancestral Cry interaction feels like Ferocious Roar's increased damage is actually works as more damage during Ancestral Cry's active time.

Is this correct or am I just imagining things?

3) Last question is valid only if my first guess is correct.
If Close Combat support gem works for combination of Ferocious Roar + Ancestral Cry.
I activate Ferocious Roar + Ancestral Cry and become Kaombear.
I attack with Maul (default attck) which also have socketed Close combat.
Will those two gems work together or only a single effect will work?

Thank you.