Accent LC (2000-05) :: 2001 - Stumbles / Hesitates From Standstill

I have a 2001 Accent, manual transmission 1.5L. The lady who had it before me overfilled it and stuffed the charcoal canister. She had this replaced, but when I bought it she reported that it still had a fuel issue immediately after refueling. She said it would stall and run rough and hesitate.

After I bought it I took it to refuel and confirmed the problem. I had read that the ECU may be trying to draw fuel through following refueling, but the new canister might be messing something up. She used to only drive it commuting distance in a city, so I took it for a long drive. Running at steady cruising state for a prolonged period seemed like a good idea, to allow any ECU learning. This partially fixed the problem! Now, most of the time, I can leave a fuel stop without a 20km drama before the car settles down, although the problem hasn't entirely gone away and it still does play up sometimes.

There's a more pressing problem which may or may not be related, however. When launching from idle, the engine goes through this 2-5 second hesitation of no power at all. If I rev up before letting the clutch out it's ok, but there's a certain minimum revs needed to avoid the problem. This is killing my clutch, and if I get it wrong it sometimes leaves me in the middle of a busy junction with no power for an uncomfortable period! During the hesitation, I've found the best way to force it is to put clutch back in and go full throttle. After 1 second or so the revs come back. The problem is much worse when the air conditioning is on.

So the clues are:
1. the previous charcoal canister issue
2. the full throttle thing might indicate something with the TPS
3. the worsening of the problem with the a/c on

Things I've tried so far...
1. prolonged cruising; seemed to improve things after refueling but overall fueling issues not fixed.
2. disconnected the battery -ve and applied brake light circuit to drain ECU capacitor, then left for any power-hold relays etc. then reconnected battery and took it for a normal drive for 30 minutes or so. No effect.

...and things I've yet to try (all gleaned from searching this forum)
1. checking / replacing plugs and HT leads
2. checking / replacing o2 sensor
3. checking the TPS plug connections. Checking the sensor itself sounds expensive - would it involve more than standard OBD?
4. checking vac hoses, in particular the hose which draws from the cannister
5. checking alternator (not sure how); the worsening of the problem with the a/c on could indicate low power getting to injectors etc? (bit of a wild guess)

In a former life I was a diesel engine calibration engineer, so I know the tricks which manufacturers can put into ECUs. What I don't know is the tricks specific to this car.