I would go for the airsal or metrakit HM, the others are way to high reving for your exhaust!
I'm not familiar with stroker cranks...Aloha, I am currenty using a Malossi Replica stock tuning and this is my strongest cylinder. It is also "de-tuned" (I have a 42mm stroker crank and so the ports are 1.5mm lower and giving less duration.) I have used Polini Evo, tuned malossi, airsal, TP and some Chinese clones and none have the torque and in city power that this stock replica has. I have a tuned malossi replica that does not have the torque and power that this stock one has. --- don't ask me why! Maybe the combo with Yas 16. frank
17,5mm carb can do fine with all these cilinders. Bigger carb just gives more power (especially on the MHR).
I woul mix my own fuel if I were you. The oil pump just doesn't give enough for these kind of cilinders.
If you realy want to keep the oil pump instead of mixing yourself, I would go for a Polini 70cc cast iron cilinder or another low reving cilinder.
I'm not familiar with stroker cranks...
Usualy cranks have a 80mm conrod. Does a stroker crank have a 85mm conrod?
Or is it a completly different thing?
You can also use the more low reving cilinders with a 12mm carb. It won't give as much performance, but fuel consumption will be less.
Note that a 70cc cilinder uses more fuel than a stnd cilinder.
From your list, I would choose the Airsal (if you'll keep the oilpump). An other exhaust will give more power, think of Yasuni R or Giannelli Shot. Things won't break if you trow a dip of oil in the tank before you refuel and use good oil!
Other good 70cc exhaust are: Technigas RS70, Polini for race, Top Performance Nardo, Stage 6 Sport, Bidalot S2.
There just has to be one of those in Canada