Yes they will work fine but metering and focus will be manual only.
I have the PB-6 and I'm not sure about mounting. You may need to use an extension tube between the body and the bellows to eliminate hitting the prism housing or the hand grip. I'll try it on a couple of my older bodies. I know a tube is necessary for some of the Pro digital bodies.
edit: OK. you don't need an extension tube but you need to mount the bellows in portrait position to avoid the hand grip. After it's mounted you can then rotate the bellows mount into the landscape position if you like. I just tried it on a D80 and a D200. Same result.
With a small extension tube you can mount the bellows in any position. A 20mm extension is fine. A 12mm extension is not quite enough.
Just one more comment. Neither the bellows nor the TC-14A is compatible with G lenses. You need to use lenses that have an aperture ring, either an AI/AIS manual focus lens or an AF lens. What lenses were you planning to use?
The AFS 18-200mm won't work with the bellows or the TC-14A.
If you want a lens for the bellows I would recommend getting the AF 50mm f1.8D. It's a good focal length for macro photography on the bellows and will also work perfectly on your D70 as a low light companion to your zoom. On the bellows you still need to use an external meter and experiment with shutter speed and aperture settings. It will focus and meter just fine on the D70 body.
The TC-14A won't work on your zoom lens either. Actually I wouldn't use any TC on that zoom.
The TC-14A is used on manual focus lenses 200mm and below. It can also be used with AF lenses below 200mm in manual focus but without metering.