Equipment: 1x Shotgun type weapon + 1x 3way Dagger/Comination Dagger(gara weapon). NOT EXCEPTION. (Eso would probably argue that, but yeah sure, once you are pro enough against Haku you can go with other options, don't worry about anything else yet) Also bring some other forms of direct melee interegrated weapon. eg. Ace Braver AM, Red Squealer AM, Shino AM2.
WB: Dual 3way Dagger Bit for Land, Slayer Bit for Air.
Bot Types: Preferably Land, Air works too (especially with Trap phase) but Land is a lot more mauverable in most cases and able to equip dual 3way, and dual 3way bit makes a HUUGE difference.
Oh and be sure that you have Packet activated, as happy as possible and with her Trap Sight ability selected.
General Strat: http://www.youtube.com/watch?v=0rt5sBkDMlE&feature=player_embedded
Meh,I would start off with AIR, especially as when you're new, unless you feel like getting lost(much easier to follow people as Air.) Even if you aren't new, people use Air because they get around things more easily than Lands. Just make sure to dash instead fly during Haku's form, or lnds, won't be able to hit him. Also, you can use a support with burst Fire, it speeds up both shotguns and 3-ways.)
As for equipment, People commonly use Kamui Staves so they can hit him outside of the arena, and I've used the halberd with decent results too(large mechs can't use 3-ways)
You can also get away with support, as Burst Fire speeds up 3-ways.
Yeah, if you're new, start off with 3-ways/shotgun, but I thought I would give some ideas to experiment with. If I were to reccomend a good bot to Haku with, I would go with a jikun with 3-way and shotgun. They have great walk, and they're legs can't be be destroyed ensuring you always have a melee. Personally, I think as long as you have 1 AIR and 1 LND, you should be fine, though I would reccomend 1 AIR and 2 LNDs for beginners.