Bottle

No, unfortunately modern dishwashers are tough places to survive these days, and they would cause the colour to fade. So to preserve the bright shine on a Smidge bottle, best to just dip it in the sink from time to time.

Part of the inside of the lid is made from a BPA-free recyclable plastic, which allows them to be 100% leak proof and help reduce the use of single-use bottles.

You can put carbonated drinks in this bottle.

I am afraid not, the bottle is one piece apart from the opening in the lid. For most uses simply applying liquid detergent and 1/3rd water and shaking will clean well enough. Bottle brushes are avaible for more thorough cleans.

The top of the bottle is 33mm. 

Sorry for any confusion the stainess steel variant is dishwasher safe, but all painted colours are handwash only - as over time the dishwasher will degrade the paint finish

I would estimate that the temperature would drop to approximately 60°C after 6 hours

Yes stainless steel finish is dishwasher safe. I can confirm that no plastic comes into contact during regular use, if the bottle was held upsidedown then the water would contact the underside of the bottle lid, that is plastic.