Update: My mistake.
I played when too tired and read deathrattles instead of battlecries.
Original: Rylak Metalhead did nothing at all when destroyed. It didn’t trigger the Rylak next to it, nor other minions with dr.
First I thought that since FFF (Free-flying Feathermane) was pulled from my hand, there was nothing for Scourfin to put the boost on.
I tried again and had a Kaboom Bot in the mix just to be sure I wasn’t mistaken.
The Rylak died - no bombs flew,
so making this report.