As a quite experienced Tau player my opinion is that you should be able to take his list.
He has surprisingly short reach to be a Tau player, the only weapons that have a range of over 30" are the railgun on the Hammerhead, all his other anti-tank weapons are range 12" (Fusion Blasters).
This is not unusual for many Tau armies, they wait for the enemy to get in close and then pulverise them and Piranhas are excelent at anti tank work as they are most often greatly underestimated. This doesn't mean he won't be able to deal with armor though, particularly lightweight Rhinos.
He also has only one XV-8 suit (the commander), and has kitted it out with weapons having a max range of 18" - good for you!
Also not necessarily, the Fusion Blaster is excelent for insta killing Marine HQ's and the Cyclic Ion Blaster is also not bad due to its rate of fire and AP-1 capability. The Tau commander is in a specialised role as he should be, which means he won't be a danger early on but when marines get close he has some nasty firepower available.
Based on that I'd agree with the idea of getting transports for your troops, as he has no Kroot-screen he will be very vulnerable to assault, and those Rhinos will help you get there faster.
This I have to disagree with, even Pulse Rifles aren't bad at killing Rhinos (I've done it rather often myself), while 5th Edition's sprint ability makes infantry pretty fast on their own. Also since you can't assault out of Rhinos the chances of being entangled and left out in the open are considerable and not to be ignored. I would say leave the rhinos at the Fang, Tau just turn them into so much scrap.
Usually a Tau player would love to see an opponent lining up a couple of Rhinos in his deployment zone, as XV-8's with Missile Pods will stop them dead in their tracks (running two units of Deathrain suits (twin linked missile pods) usually stops both Rhinos in my first shooting phase, 5-6 str 7 hits will do that to a Rhino, smoke launchers or not.
He does not have a single Missile Pod in his list, so nothing to worry about there. Beware however that those Firewarriors can glance a Rhino with their str 5 Pulse Rifles with a lucky 6, so be careful.
A lack of missile pods does not mean Rhinos will be a good idea or have an easy time. Fusion Blasters, pulse rifles, burst cannons, practically everything in the Tau list save the Ion Blaster will be able to stop the Rhinos in their tracks, never a good thing vs Tau IMO.
I think the bikes are a good unit against this list, you may consider giving the bikers melta (if SW can have that, I don't know much about them) to try to pop that Hammerhead, any good Tau commander would take the Disruption Pod for the Hammerhead, giving it a automatic 4+ save against shooting, but remember that this is only against shooting from more than 12" from the skimmer, that means that you could waste a lot of shots with your lascannons without making as much as a scratch on the Hammerhead, but a couple of meltas inside those 12" could really ruin his day.
I'm a bit out of practice but I've never run Disruption Pods on any vehicles nor have I seen others due this, perhaps its a change with 5th Edition effecting wargear but in any case I have to disagree here, the Hammerhead is not a primary concern or target and should not be the focus of the bikes until the infantry is dealt with. The Bikes however are a great idea and there I have to agree, however in application I'd say they are best used to lock Tau in combat while the rest of the force closes in. Run the Blood Claws and Grey Hunters across the field and turbo charge the bikes up a flank. By turn 2 or 3 while the infantry should still be out of rapid fire range of the Tau the bikes charge in and lock the Tau Firewarriors in close combat keeping the Infantry free from the nastiness of rapid fire pulse weapons and gives them a fighting chance to close the distance. Throw a Melta gun into the Grey Hunters and some Power Fists and the Tau vehicles shouldn't be too much of a problem but focus on the infantry first. The Tanks are nasty but overall their firepower is a lot less than that of the Tau Infantry and their BS isn't spectacular either even when upgraded, Hammerheads are potent but their real strength is as fire magnets, they draw attention from the rest of the army so that those Firewarriors and battlesuits can continue to sow destruction unhindered.
Assault Marines would also be god against his list (if you can take them).
No, no assault marines, too low WS and too high cost with Space Wolves, they aren't worth it.
I don't know if the Powerfist and Powerwpn are worth it against his list, as the most likely target for your blood claws are the pathfinders and Fire Warriors, and they will be loosing against the Blood Claws anyway, and you might in fact want the close combat to extend into his assault phase, so he does not get to shoot at you in his shooting phase. His unit of Stealth Suits will also go down to the BC's pretty easy, even without the powerfist/wpn.
At least one power fist should be in each squad, insta killing the Commander and Stealth Suits is a nice thing to be able to do, it may make combat a bit shorter but a couple fists shouldn't turn the tables quickly anyway and besides the Tau units most likely won't survive the first round of combat anyway, there just aren't enough of them.
His HQ you can afford to somewhat ignore because of the low range of his weapons (max 18") and the 2+ save. But remember that if you have clear line of sight with a lascannon one round you should take the shot. Shas'O and Shas'El are T4, so thats instakill if you manage to wound it (he might have a shield generator for that 4+ inv save, but I say it's still worth a shot).
Unlikely if the player has any idea what he's doing, a Power Fist works better in my experience and keeps the commander from shooting. Also I'm not sure if
FNP was changed in 5th but any shot that causes insta kill should also ignore
FNP.
His Piranhas will probably try to outflank you, drop their drones and then try for some shots against rear or side armor, do remember that drones can be a threat against your vehicles if they get the rear armor as their str 5 carabines can glance on a 5, and penetrate on a lucky 6. They are not very hard though, so a few shots their way will send the discs crashing to the ground.
The Piranhas should be a priority target anyway, the Space Wolves don't have the speed to chase down Piranhas easily and their speed and firepower is formidable, not to mention they tend to turn tanks into scrap metal real fast drones or no drones.
hmmm.. I do feel a bit like a traitor to the Greater Good now, but good luck in your next battle against him 
Rune
Eh I started the game with Tau oh five... six years ago or more, don't keep up with the army now, got boring when I won too much, but now I get to help others kill Tau which gives me a warm fuzzy feeling. Anyway Tau are very specialised it really comes down to picking the army apart and knowing how to minimize their strengths and maximize their weaknesses. A Grey Hunter squad can slug it out almost all day by itself but a Firewarrior unit needs support to work well, thats always been the weakness of the Tau. Even worse now since the True Line of Sight works against Tau very nicely.