So they should have fired off a salvo of Long Lance at long range and then declared that they were "dumping ammo" before closing the distance with Taffy 3? ;)
Well... I mean, kinda actually.
Something to consider is that during the operation, the smoke screen and aggressiveness of the American escort ships convinced the Japanese that they were up against heavy ships- some of the reports that survived on Japanese ship logs report 'confirmed' Essex-class carriers, heavy cruisers, one report even IDs a Pennsylvania-class battleship! In a case like that, throwing eight Long Lances (she had two four-packs on each beam) isn't the worst way to start things off- you can't see into the smoke screen very well, but that means they can't see OUT all that great either. No big deal for the radar-guided guns of the American 'cruisers', but their lookouts would still struggle to spot Long Lance wakes through all that crud. So just throwing them and seeing what happens isn't the worst move- at best, lucky hits, and if not at least throw the American formation into a chaotic mess of evasive maneuvering (not unlike the chaos the Japanese formation became, actually!). And of course, with the reload magazine, Chokai could be ready to fire again soon- it might not be REAL soon, but another salvo can be loaded, and if all else fails there's the tubes on the other side of the ship too.
The problem is, again, the double-edged sword side of things- it seems the reloads are what actually caused the fatal damage to begin with (CASE was not a standard feature on Japanese heavy cruisers), following the hit on the tubes the fires burned hot enough to start touching off AA/secondary gun magazines and the reload locker. Launching the first fish salvo and reloading wouldn't have helped much- the tubes were mounted port-and-starboard in two four-packs on each side, but the reloads were kept amidships. Emptying the tubes would just have meant the shell from White Plains still would have found a torpedo tube set (during reloading, one imagines), touching off the same fires and causing the same secondary explosions in the reload locker- which isn't AS full, but still has all the reloads for the far side of the ship sitting there waiting.
Hard to predict what REALLY would happen, of course- and it's even hard to really get a look at what DID happen, with Chokai being lost without any survivors (the few that lived died when the destroyer that rescued them was lost later in the battle). But yeah, firing those torpedoes at the impressive range Long Lance gives and just hoping for some luck wouldn't have been the worst idea for the Japanese, given the opponent they thought they were up against. It likely wouldn't prevent the loss of Chokai or the other ships they lost in that engagement, but it might have ensured a bit more effect on the Taffy fleet than they actually caused. With Long Lance being able to slice a heavy cruiser apart with one hit (such as USS Northampton, or USS Minneapolis), the idea of one hitting a CVE is disturbing.