The ventilation question has been answered.
The wheelie question is up to you. Gearing and suspension can both or separately gain you wheelies. My first question would be to ask, why on earth would you want wheelies? They waste power and are an annoyance, because once you get them...you have to actively try and get rid of them or else they will occur all the time.
In order to get wheelies via gearing, you need fewer teeth on the clutch bell and more teeth on the spur gear. More when compared to whatever you have now. To help the gearing, soften up the rear and stiffen up the front suspension. That means weaker springs in the rear and stronger ones in the front. This will allow the vehicle to squat when under power and cause the rear to drive up under the front, producing a wheelie.