Two Combat Skills at once?

Paladin
1

I have maxed out Holy Shield, and it will last for 505 seconds. If I use Fist of the Heavens after activating Holy Shield, will Holy Shield continue to work for 505 seconds?

2

Holy Shield is a buff for yourself. It will run the full duration and you can use all other skills with it. You can compare it with i.e. sorceress frost shield or necro bone armor.
FoH is an active skill you cast on enemies.