The logical move is to make a deal with China.
Get China to invade instead, have them make a deal for no. Like, US stays out of it, let China take nk, have China write off 1 trillion of debt.

China actually depends on the US and South Korea and Japan for a huge amount of manufacturing purchases. While we owe them a lot of money, we're not exactly enemies, but more like two rivals who mutually benefit from each other.
NK threatens that ecosystem, and let's be fair, China would rather just own that territory in order to claim more of the sea.
It's in China's best interest to take out NK. US could never invade because it wouldn't only be bad for retaliation to nearby Allies, but it would be a highly contested point and strengthen tensions in the area.
Therefore, the best move is to convince China to just take it in a business move orchestrated by the US and Chinese governments.
China has once recently condemned nk for these arms races, I don't think it will be long before they do something.

Pre-emptive strike would be useless. China and Russia will come to NK's rescue. They won't declare war to NATO, they're not stupid, but they will support NK heavily with weapons, soldiers and supplies which will end in a stalemate just like in the 50s. The US cannot take NK, China and Russia won't let that happen. They do not want a border with a unified Korea under NATO flag.

North Korea is just bluffing. They saw what the US is doing to other countries, invading with no reason at all and bombing them into the stone ages. The only security you have as a small country against random attacks like that is nukes. NK building those is perfectly understandable and the US has no one but their own politics to blame for the current situation. I think it's pretty safe to say NK won't actually use those nukes. We just have to accept them as a nuclear power. Even if the do launch a nuke, then taking them down will happen in a matter of days as China and Russia will no longer protect them in such a case.

A pre-emptive strike is a bad idea and has the potential to end in WW3. So no, that option shouldn't even be on the table. Bombing shit out of countries seems to be the american way of handling with international problems, but it isn't the solution to everything. In fact, most of the times it just makes matters worse.

That only works if they're right next door and we can mask the build up of troops. Even if you could pull that off, China and Russia probably wouldn't like that. 

China will never let a unified NATO-US Korea sit on their doorstep. 

And US will never agree to just hand over North Korea to China, which would encourage China to take over other disputed areas of South Asia. 

Don't confuse things like "friendship" ... there is no real "friendship" in geopolitics, there is only power. 

China and US need each and are "friendly" to each, but friendly in that "girls who go to high school together, smile in each other's faces and then as soon as they turn around talk massive shit about them and would secretly love nothing more than to see the other get hit by a bus" type of thing. 

Oh no I am not under the naive idea that we're friends with China.
But what I'm saying is that with the amount of money we owe China, we can potentially work something out with them. Give China control over nk, trade it for debt write-off.
Both increases our positions globally. Again, neither of us would want to give the other this, but nk is becoming a nuisance to everyone even China.
The smart thing to do is to make the situation beneficial to both, even if it means trading something away.
China loses economic control over us debt, but gains more strength in South China Sea, us loses positioning in scs, but gains a degree of economic relief.

No.

The dream scenario is that China realizes how terrible it would be for them if the US was forced to topple the NK regime. China imposes heavy sanctions on NK until they do the following:

1.) Dismantle their nuclear arms program
2.) Establish a diplomatic relationship with the United States
3.) Allow UN weapons inspectors
4.) Cease human rights abuses

In exchange, the US and its allies offer humanitarian aid.

Of course, all this is extremely difficult when the President is dismantling our relatioship with the other NATO countries, putting SK on blast, and constantly getting outwitted by Putin. 

I’m guessing your use of "nuke" is an exaggeration but in case it’s not, the US will not use any nukes. The North seems to think that obtaining a Nuke is the only way it can retain power. In reality it is going to be the quickest way for it to lose it. Russia and China do not want to see N Korea with weapons like that and are very much infuriated that N Korea is testing them. They do not however want war because they see the US as establishing a base of operations on their borders if the South takes over the North. They also do not want an influx of people from N Korea to flood over their borders. In the end, N Korea will end up striking by accident IMO. One of the missiles they fire towards Japan or over the south will fail and fall into a populated area killing people. That will in turn lead to war.

We don’t need troops. With the Navy and air force of S Korea, Japan and the US, we could bomb them into extinction. Hit all high value targets first in a coordinated effort and the N Korean army will falter. They will be in such shock from the attack that they will give up.

You watch too much CNN