Spitting(outside)
Only brushing my teeth once on nonschooldays(Twice on schooldays)

Spitting for no good reason is kind of chavvy. Though I live in England so I don't really know "redneck".
But it is really manky to only brush your teeth once. Honestly, urgh.

If I was near you I would smack you upside the head for spitting. It's incredibly rude and there is no reason for it.

I can't say anything about your teeth brushing though because I tend to forget to do it myself.

Spitting outside - Not redneck unless you've got a mouthful of tobacco.
Brushing Teeth - Most rednecks don't brush at all

Spitting is nasty but I don't think it's considered redneck.

Nasty mis-coloured teeth or only having a couple can be considered pretty trashy but I'd say no oral hygiene at all would be considered redneck.