I haven't watched the whole video and can't tell their intensity. To me, the noises are normal. For me, they sound no different when charging at 120 volts vs. 208 volts (@ work on our L2 EVSEs, my Leaf pulls ~5.7 to 6.0 kW on them).
The noises are quite soft w/the hood closed and not incredibly loud w/the hood open. You should be able to feel coolant going thru hoses in/out of the PDM stack. Coolant pumps need to run.
The entire stack will be warm after charging for a few hours, even at 120 volts.
'13 Leaf SV w/premium package (owned)
'13 Leaf SV w/QC + LED & premium packages (lease over, car returned)
Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.