For third DWI is it always a felony

Pretty much, a third dwi/dui is a felony.

How successful can I expect to be challenging a "super-speeder" fine in Georgia?

Speeding is absolutely part of the Interstate Compact, just like driving privileges. Sorry you don't like what Georgia is doing. Pay it - or don't.

How can I best defend myself against a speeding ticket based on a radar reading immediately before changed speed limit sign.

You're not a lawyer, and there are multiple problems in your analysis. First, radar is radar. It's not based on anything the officer said. You...

When did my diversion officially end, and where can I view/obtain an official, legal issue of this date? Expungement question.

It will be one year (possibly two) from the date you signed the diversion.

Living in Kansas. Warrant in Oregon. Misdemeanors?

No, you won't be extradited, just have warrants and be detained if you get pulled over. Also, Oregon could decide to extradited you, it's just...

Are second opinions a thing? If so, how do I go about getting one? Have an attorney, but willing to pay for second set of eyes.

Ask your lawyer how many trials he has had. Always ask that of every attorney, because most of them have never had one - and never will.

Can a detective arrest me for a bad check that i did not write and the bank classified it as a stop payment and so did my county

Yes, anytime there is a warrant you can be arrested. How do you think all the innocent people that get out of prison feel?

Will an old SIS sentence show up on a background check.

It likely won't show up. If it does, ask them for a copy of it so you can see how it was found.

Double jeopardy

It's more complex than that. It depends on the specifics of each charge, the wording makes all the difference.

Pay your Colorado ticket. If you can't just pay it because you have to appear in court then I'd get a Colorado lawyer.