Brewing Monitors

This is my first solo project so I have a few questions. Ive just been following step by step instructions and doing research on the inner workings of circuitry and im gonna try my hand at this.

So heres the idea... I want an alcohol and carbon dioxide monitor on top of my airlock to measure what comes out over various times of fermentation. I also want to tape a temp sensor on the carboy to control a brew belt(120 ac). The bi-hourly measurements will be recorded via sd shield. I would also like to have my 16x2 lcd monitor also attached to a momentary push button so if im curious i can hold the push button and get a current readout.

Ok... General idea out of the way here are some of my questions.

Concerning the sensors... Im using the boozeduino to grasp the sensor rig. It uses just the sensor and a 9v battery with a power regulator. Its my understanding this is because of the mA draw. I could do it this way but there are mq3s attached to boards already but not too many tuts on using these. Will this remove the need for the 9v? The co2(mg811) is pretty close to the same thing. Either a sensor or a prebuilt board and sensor. Also i was considering running the whole thing off my pi and using usb to power 2 sensors and arduino. Is this possible?

Now on to temp and belt. Ive seen setups to control 120 ac outlets. This will mostly be outta sight outta mind so i was wondering if there is a shield or power strip ready for this? Im not sure how comfortable i feel with 120 and a newbie circuit.

And last question... With the lcd if i put the button on the power and have it off most of the time will the code turning pins on and off cause any errors if the lcd is off?

Thank you