Technically, this is possible at level 35, the lowest level you can gain enough skill to fish there (albeit, with get-aways). You can be summoned to each of the lakes.
Currently Lake Ere'Noru (above Allerian Stronghold) has no mob spawns around it. At least I’ve never seen any in all the time I’ve fished there. Only four pools spawn in it, but if one was fishing with a seldom used alt he/she could leave the character there and log in from time to time and fish any pools that have spawned.
But this lake requires 405 fishing skill to cast. So, as you said, this could conceivably done with a level 35 character with 300 fishing, a +100 lure and something like a big iron fishing pole (+20). But I would recommend level 45 at least so that the character could read Master Fishing - The Art of Angling and be gaining fishing skill while trying for Mr. Pinchy.
However, this could still be problematic. The character will fill up his/her bags with Furious Crawdads, Golden Darter and motes of water. And that’s assuming the player destroys everything else fished up. They could destroy these as well, but at over a gold each in the AH I’d be loathe to do so. On top of this the player will have to be re-supplied with +100 lures. Of course if the player has a second account with a character on a flying mount, or a friend with the same, it’s all good.