I've been testing strategies for Normal difficulty, and it seems as though Chapter 5 is the first really massive difficulty spike (the Eve escort mission is also tough, but not too bad if played conservatively). I'm not too convinced that 5 can even be played aggressively on Normal or Super Cop - making egregious use of insta-kill Shadow can give some breathing room but not much.

Any ideas?

The Rookie strats for the first gate are possible on Normal, but they leave you with almost no health for the next gate (when the Joker jumps down). You can have some wiggle room by equipping Shadow then mashing R+A, which gives you a chance of having him kill one of the clowns that spawn on the bridge up top.

One of the really BS parts of Chapter 5 is that enemies can still attack during the cutscene showing the unlocking of the gate that leads to the underground passageway - and that's not even getting into the canister boss.

Not on Normal. It does seem a little bit faster to detonate each canister as they're thrown rather than stack them though, since it gets rid of the slow motion quicker.

However, if there's a clown that's spawned too close to the van, it's safer not to do it because you'll probably lock on to the clown instead.