I really appreciate all of this, I have decided against getting either fish and I'm focusing on instead upgrading the filtration in my tank since its current design clearly isn't working well enough.From what I've read, Koumansetta rainfordi (the Court Jester/Rainford's Goby) will peck at and maybe eat some filamentous algae, but I've heard mixed things as to whether or not they'll eat enough to be useful for controlling the algae.
I've also heard that at least some Amblygobius species (the Link's Goby being Amblygobius linki) will eat filamentous algae, but I wouldn't expect them to control its growth from what I've read.
In both cases, these fish are primarily carnivorous, so while they may eat hair algae (or potentially just pick pods and detritus out of it), I wouldn't expect them to effectively control it.
I'd get a lawnmower blenny but I'm concerned about my watchman goby killing it... although she did accidentally just spend a solid month in my rear sump chamber so maybe she's feeling less homicidal right now. (My aquarium has a DIY AIO design and she decided to leap into the filter area without my noticing where the heck she was until I found her by accident, perfectly healthy but clearly wanting to be returned to the main body of the tank.)