In hindsight, Randuin's Omen might be the best item to rush on Wukong Tank(even though you're in the support slot, you are a substitute for a real support so it's more correct to call yourself a tank...on my mastery page I call it SS short for substitute support and apply that also to mages or assassins or whatever). You take Relic Shield for healing your ally as well as for extra health to protect against bursting. I didn't buy Randuin's Omen and instead I've been rushing Thornmail. At any rate, you need to get tanky, so your mastery page needs to give you bonus armor and MR based on your bonus armor and MR. Picking up Black Cleaver is still what you do, which helps out your ADC and really your whole team(you can trigger it on the entire enemy team potentially with your ultimate, although probably not the full value on all of them, it's still nice). Don't really need flash as you have your own jump and invisibility, prefer to take barrier to combo with all the tankiness. As for tier 2 boots, as with any other tank, you either get Ninja Tabi or Swiftness Boots, depending on whatever.
A big mistake I've made from time to time with Wukong is forgetting that I'm not as tanky if fewer enemies are around. And of course there's always the threat of your allies not following up on your initiation. I guess if you're super worried about that then you can take flash and let them think they're initiating, then flash in to do the job yourself.
As for Leona Jungle, her clears are fine in mid/late game if you take Bloodrazor which is valuable due to the changes to her ultimate. She can use any Spellblade item effectively due to being a melee user that can scale with AP. Probably if you're taking the keystone I suggested you'd go for IBG, but not sure. I'd suggest building an amor item before IBG if you need the armor since IBG gives a burst buy armor value of 40 which is silly because you'll have 0/15/25 until you complete it so you'll be in trouble in duels and skirmishes if you have lots of mana you're not using and not enough armor. And of course you always have to buy MR. The new Abyssal Scepter is great for her(actually I might start rushing it on her from now on due to the CDR and raw damage it provides) and Wit's End is pretty solid as well. I find it amazing how unfavored Wit's End is as an item at the moment personally.
Half my problem is I keep changing champion selections so quickly because once I get S grade a time or two or so then I move onto the next one for my chests. I'm sure I'd have a firm grasp on how to play them in those positions even better if I just practiced them more. Of course, if my success rate is extremely high, like success rate 100 percent or close to it, even with as low as two games, I'm way more confident with recommending it to others than I would be a champion(like Jhin support) I lost a lot with before I started winning.