The Caldari Navy Hookbill has 0% base EM resistance and 20% base thermal resistance. Your opponents in PVP are quite likely to select ammunition that does either EM or thermal damage if they can. So I would recommend to put at least one EM rig into your fitting, that gives you 38.8% EM and 30% thermal resistance together with the DC.
For that reasons it is generally a good idea to plug such big resist holes for PVP. Three resist rigs though are not used often. The effect of additional resist rigs is rather small, and they don't help you at all if your enemy shoots any other damage type.
The first EM rig makes a big difference, without it (only resistance is from the DC II) you have 7.2k EHP against EM damage only. One EM rig brings that up to 8.09k EHP, which is only slightly below the 8.2k EHP your all-resistance fit would get. Against thermal damage your fit has 7.97k EHP while the three extender fit has 7.69k EHP. Against your strongest natural resistance explosive the resistance fit only gets 7.64k EHP while the three extender fit gets a huge 10.2k EHP.
You could probably get away with a three extender fit if you are a bit careful about which ships you engage. Amarr ships using Scorch would be very dangerous to you as Scorch is almost all EM damage. But as you have excellent range control, Minmatar ships with Auto Cannons would not be able to deal EM damage to you, they have to switch to Barrage at your engagement range.
I like the three resistance rigs for cheap T1 fits because the Field Extender rigs are much more expensive, but in a faction frigate that small costs doesn't matter anymore. I'd go with a 1xEM 2x Field Extender rig here.
Another variant of your fit would be the following which has only 80% of the EHP but does around 23% more damage:
[Caldari Navy Hookbill, Dual_Web]
Damage Control II
Ballistic Control System II
Medium Azeotropic Ward Salubrity I
Limited 1MN Afterburner I
X5 Prototype Engine Enervator
X5 Prototype Engine Enervator
J5b Phased Prototype Warp Scrambler I
Rocket Launcher II, Scourge Rage Rocket
Rocket Launcher II, Scourge Rage Rocket
Rocket Launcher II, Scourge Rage Rocket
Small Anti-EM Screen Reinforcer I
Small Processor Overclocking Unit I
Small Ancillary Current Router I
Another personal favorite of mine is an armor TD and dual-web fit:
[Caldari Navy Hookbill, Dual_Web copy]
Damage Control II
400mm Reinforced Rolled Tungsten Plates I
Balmer Series Tracking Disruptor I, Optimal Range Disruption Script
Limited 1MN Afterburner I
X5 Prototype Engine Enervator
X5 Prototype Engine Enervator
J5b Phased Prototype Warp Scrambler I
Rocket Launcher II, Scourge Rage Rocket
Rocket Launcher II, Scourge Rage Rocket
Rocket Launcher II, Scourge Rage Rocket
Small Ancillary Current Router I
Small Anti-Explosive Pump I
Small Ancillary Current Router I
The dual-web AB Hookbill has excellent range control, you can kite at the edge of scram range against nearly every other ship without problems. The tracking disruptor means that any ship with short-range weapons will do only minimal damage against you.
One very important aspect when flying an afterburner Hookbill is taking some Javelin rockets with you. Any MWD kiting ship will fly circles around you and with only an AB you have no chance of catching them. With the Hookbill range bonus the Javelins go up to 22.8km far. If you fly away from your enemy in a straight line he has to fly towards you to follow you, this extends the range of your rockets another few kms as your enemy flies towards them. This is usually enough to drive away most kiters without Skirmish links.
