Impact - yes
Ignite - yes, but only if target isn't fire immune
Flame Throwing - neither range increase talent works on FFB
Burning Soul - yes
MoE - no, MoE is a proc on a per cast basis, thus there is only 1 chance for it to proc.
Critical Mass - yes
Firepower - yes
Pyromaniac -yes
Combustion -yes
Molten Fury - yes, it doesn't double dip though. The double dip seems to only occur when the talented effect mentions both Frost + Fire receiving the buff individually. MF is a universal effect that buffs all damage types (Nature for example if we had any) The exceptions being the range increasing talents.
Elemental Precision - yes, and it doubles up
Ice Shards - yes, unaffected by immunity, the damage is applied directly, not by a debuff like Ignite.
Piercing Ice - yes
Frost Channeling -yes
Shatter - yes
Winter's Chill - yes, unless immune to Frost damage
Arctic Winds - yes
Winter's Grasp - yes
CoE - yes, and doubling up
Improved Scorch - yes
DK Frost vulnerability - yes
I haven't seen any information posted on the effect of single school damage, from gear / consumables. It likely is, but how and to what extent I'm unsure.
Your question on the
[Flask of Pure Death] however is a good candidate for doubling up though. In the end it's likely a moot point as this behavior (doubling up) will be nerfed before release.