Phasers. Phasers all around and 3 Phaser relays for tac consoles. One Hargh' peng torpedo fore. For your tactical bridge officers you need beam fire at will one and two and tactical team one. Unmodified weapons attacks are "Mostly Useless". Tactical team one is in there to give you at least one shot at computer assisted shield distribution. You will need to choose engineering skills like warp plasma and aceton beam to add some more damage and control and for science you may want a tractor beam in there for more control. You can of course include an aft launcher. Just depends on your intent for that particular mission. If you intend to be in position to fight both ends of your ship then do so.
You do this because the bridge officer lay out severely restricts you from building a traditional sustained damage output based on modified energy and torpedo attacks in combination with tactical buffs. You can only choose one of those options and the option that's going to have the most time on target will most likely be energy weapons, specifically beam arrays. The Hargh'peng torpedo doesn't accept attack modifiers it is fired 'as is' and is a solid attack with secondary effect. You do phasers and phaser relays because you have ONE REALLY BIG ONE and well since we choose energy weapons why not get the most out of our 3 tactical consoles? We could waste a console on a kinectic for our torpedo but I believe it does at least two damage types anyways so best to just focus on our energy weapons.
As you do about a billion of the STF's you may start to think "hey everythings the same every time". This is true. And it makes positioning your whale very easy. So easy that you may feel you can run cannons or cannons and torpedoes in a classic escort load out. You could, but your ship would still lack the bridge officer powers that make those weapons so yummy. You could manage 2 torpedo modifiers or 1 cannon modifier, or one of each. But if you do that you extend the amount of time in which you'll be making unmodified attacks plus you'll now want to have a torpedo console to bring your damage with those attacks up to what the Hargh'peng does on its own.