Sounds like you got one of those planes assembled at the end of shift on Friday. Do you have an experienced RC pilot available to help you? Some of your problems may not be as big as you think but it's hard for us to visualize without being there. The inverted vent tube is a definite show stopper and the fuel stopper should have to be forced out. If it's falling out then when your engine runs it would blow fuel out around it and not be able to keep fuel pressure on the carb. Tighten the screw in the center of the stopper. If it has been over tightened and the tank cracked then you will need a new tank... call Horizon Hobby for an RMA.