I think these two champions are underused in the jungle now, considering the new Feral Flare item makes jungling with them not only possible, but very viable. Both have ways of sustaining and ganking, and both rely heavily on on-hit effects and auto attacks for damage. Also, they are exceptional duelists (we are looking at you, Fiora) and can excel in counter-jungling, counter-ganking, and making the enemy jungler have an all-around bad day. So why are these champions not seen in the jungle more often, if not commonly? Well, I believe that this is an example of the meta shaping some "Do's" and 'Don'ts" in players' minds. I have examined both champions and put their merits down in seperate sections below. If it sounds like I'm trying to sell you on this idea.... well, I guess it's because I am.
---Fiora---
Fiora is in a really weird spot as far as her kit goes right now. A rework is being tossed around, and because of this, she isn't getting much attention from Riot as far as her current iteration goes and is definitely not on the radar for most players. However, her kit DOES bring a lot of interesting things to the table. So, lets go right down the list of her skills, starting with her passive.
I will admit that Fiora's passive leaves a lot to be desired. The health regen from it isn't that impressive, especially without an enemy champion around to duel with. While lackluster, it IS still free health regen. This can help get her through the early jungle and help her survive through her all-in-style ganks.
Fiora's Q is really interesting in the jungle. It adds a lot of damage to camps (only spam when you have blue buff early on!!), but that is not what appeals to me. The instant-reset gapcloser is her best tool for ganking, and can reach virtually anywhere in lane with ease, given there is an enemy minion wave present. Q to a minion, then immediately to a champion for a suprise gank and, coupled with your E, a huge burst of damage. Also, running Udyr-style at your opponent and then double Q-ing will do loads of damage. Max this.
W. Well, there isn't much to say here. It blocks monster damage, so while you have blue buff (or spare mana) you can take a little less damage from buffs and golems. It also helps take less damage from enemy junglers and during ganks, I guess. Oh, and it gives passive AD. So that's a thing. Not too exciting in the jungle, but to be fair, it never really was in lane, either.
E is where it gets fun. Say hello to an auto-attack resetting, speed boosting attack speed steriod of doom. A good Burst of Speed coupled with your Q (and a red buff thrown in, if you want) ensures that your victim will have a hard time escaping your heavy-damage gank, even through a flash or escape. I would advise starting with this in the jungle, and using auto-E to clear your first buff. Oh ya, you can start either. And gank level 2. Why not?
R. If you're a Fiora player, I don't have to explain why this ability is nuts. I would argue that it is an even better asset on a jungler than a laner, at least in the early and mid game. If, by some miracle, your helpless victim escapes your two gapclosers, 6 second movespeed buff, and all-in attitude and decides to seek refuge under his or her tower, press R and watch them die a helpess, pitiful death. Oh, and your Q might be back up, just in case you wanted to avoid ANOTHER tower shot.
BUILD: Feral Flare, obviously. Rushiing a Tiamat will help your clear times and damage, and a Hydra should be in your near future anyway as Fiora. Berserker's Greaves, or even Mobility Boots are a good idea. After that, Last Whisper, Guardian Angel, Randuin's, Hexdrinker.... you know what to do.
RUNES: I would use Attack speed Marks and AD Quints. Armor yellows and Scaling MR glyphs also work.
PENDING FOR TEST: Fiora's Ultimate applys on-hit effects like Cleave, so does it apply Feral Flare? If so, this champ should be banned out.
TL;DR Try jungling Fiora with Feral Flare.
---Irelia---
Whew, for a first post, this is quite a read. Anyway, I'll continue. Irelia has made her mark as an on-hit, auto-attacking bruiser, who melts carries and gets out laughing. So why not add an item that seems to fit perfectly on her? Passive healing on-hit? Check. Magic damage on-hit? Check. Good jungle sustain? Yup. A good gapcloser gank, complete with CC? You betcha. Let's take Hiten Style up a notch (not that it needed it, Riot 0.o pls dont nerf) with Feral Flare Jungling: Irelia addition.
Passive: Well, this is an awkward start. No, it doesn't help in jungling. Good luck trying to stop her ganks, though. Let's not forget that junglers fight in late-game teamfights, too! and with the effenciency of Feral Flare, you won't be feeling that gold differential nearly as much.
Q: Oh, good, I thought I was losing you! This finishes off low-health jungle creeps in a flash (or, more accurately, a dash) and also is your main tool to close the gap on ganks. Looking familiar? Say hello to a Feral Flare proc, by the way.
W: This. This gets me excited in the jungle. Let's take a build based around attack speed, give it true damage, and make it heal too! Why not?? Pop Hiten Style at any time, don't worry, the sustain is REAL. Careful not to keep that health TOO high, though....
E: So, we have a gapcloser, plenty of damage and some sustain. As long as we can stick to them... Oh hey look! While lane Irelia has to watch her health bar for things like trading in lane, ganks, ignite, silly things like that, jungle Irelia can feel free to manipulate her health in the jungle, like an AAtrox or Olaf. Irelia, however, will have her potential victim's health bar in mind, though. Keep your health just low enough to stun the enemy when you gank, and a kill will surely follow. It slows, anyway, so if this seems to risky to you (or the opponent is REALLY low), you can just gank anyway. If they are at like 20 health, why do you need a stun anyway??
R: Yeah, kind of underwhelming. It always is though. If your target is running under tower with low health after a bloody battle, mashing R a few times should pop that running bag of gold open real nice-like. Tower-diving as Irelia isn't too bad anyway, but not having to take the risk is always the best way to go.
BUILD: Feral Flare, Trinity Force, then full tank. Getting a tank item to help survive before Tri Force can be very helpful, even if its just a Giant's Belt.
Runes: AS Marks, AD Quints, Armor Seals, Scaling MR Glyphs. Second verse, same as the first.
TL;DR Try jungling Irelia with Feral Flare.
Whew, that was an adventure of a first post. I commend you if you got this far, and thanks for reading!! :D