@PDX Joe
On DC side not much to worry. Meanwell great design. In meanwell test they short circuit DC side for over an hour and driver still works. Plenty of protection on DC side.
Usually we use Constant current driver and it is not like DC output will jump crazy high current if short.
For high power constant voltage driver like the hlg 185/240/320 42/36. It might be good to use a 2 or 3 amp fuse to protect each cobs incase one or more cob in parallel fails and your remaining cobs get excessive current.
On AC side I think connecting ground important. A fuse would be nice too. But on AC there is high inrush current. So use a 'slow blow' type fuse if you want of slightly higher rating like 10 amps.
A fast blow 2or 5 amp may blow due to inrush current.
About thermal protector.
If metal encased thermal protector then very careful and avoid this mistake.
http://rollitup.org/t/pictures-of-your-diy-lights-post-your-pics.871625/page-22#post-12059686
I prefer plastic encased thermal protectors.
Unfortunately many of these thermal protectors are rated too low for DC. Discrimination against DC
Example 125VAC 8A but only 24 VDC 8A
They are very well suitable to be connected to dimming in drivers as it is between 10-12v and very low currents.
Never tried them on AC side. But they seem more suited for AC side than DC side, which is usually 25-40v for popular cobs
Normally open type better for meanwell dimming.
Normally closed for AC or cob DC side
@Growmau5 I have some extra normally open types 55C cutoff thermal protectors
Great for dimming light incase overheat due to fan fail in active cool design. PM me if you want a few to play around. If you like you can make a video to explain how it works.