Hey hey, I wish ya the best of luck in the tournament! A few of my thoughts.
1. I think you're gonna need some more markerlight support. You only have one dedicated source and if your opponent knows anything about playing against Tau, they are going to get wiped out turn 1, hard. If formations are allowed, may I recommend the drone net formation? You really need them as they are a very effective force multiplier. Otherwise we're all stuck shooting at BS3 and that's just not reliable.
2. As badass as the rail rifle on the Broadside is, It just doesn't put out enough shots for the point cost. You've got enough fusion blasters that it's probably more worthwhile to give them all HYMPs.
3. No real need to take the commander's squad as bodyguards. He's already and IC and so they pass look out sir's on a 2+. Odds are low, and he's durable as is. You could save 20 points by just doing that. Honestly, if you're hurting for markerlight support, you could change up some of his kit, drop the bodyguards entirely (or run them as monats) and make the commander a drone commander with missile pods, tanking for the drones.
4. The Fireblade, he's a nice fun cheap HQ, but he won't be effective for several turns. His ability only works if the squad hasn't moved that turn, which is great if you have them camped on a back line objective. However, you've put him in a fish, which indicates to me that you want them going up and being aggressive. As such, it'll be at least 1, maybe 2 turns, before they are comfortably parked and able to use his ability. Maybe the points could be better allocated elsewhere?
5. I would also maybe give the riptide an EWO. Nothing quite like being able to intercept, throw down a pie plate, and just delete an arriving enemy unit before it even gets to do anything. Especially at AP2. It's a steal at only 5 points for the model. It also gets in your opponent's mind as to where they can place their DS'ing things as to avoid the riptide.
6. Kroot reinforcements are interesting. But they're not very good at melee and are paper thin. Short of giving them sniper rounds and parking them in some forests/ruins, they're gonna be shredded pretty quickly.
Anyway, those are my thoughts! Hopefully this didn't come off too critical, I just want to see Tau succeed
If you have any further questions or some of my advice doesn't make sense, please do let me know.