1) Yes you can use your trusty Luna Pro and set the camera manually.
2) I don't know if Sunpak makes a dedicated Nikon Digital SLR module for your flash--check with Sunpak on that, but I kind of doubt it. You still can use it in manual mode.I don't know what the trigger voltage is with you flash, I advise checking with Sunpak on that too.

Not sure if the D70 has a PC socket for the mains flash units; if it doesnot, Wein makes a hotshoe unit that has the PC in it. Check the trigger voltage of the studio lights as well. you may need the safe sync version of the adaptor.

You can use the AS-10 to add a PC socket to the hot shoe. Or you might be able to use the SU-4 to shoot wirelessly using the on camera flash to trigger the strobe. That's how I use my 18 year old SB-24's wirelessly.

Or if you're using regular studio strobes, why not go wirelessly with something like the Wein transmitter and receiver. That's what I use. My Dyna-Lite power packs have built in Wein receivers.

The D70 doesn't have socket for the sync cord but does have a hot shoe. I found it really discouraging when the ones who work at the camera shops don't know what I'm talking about when I asked about off camera flash. I usually use my flash on a side bracket to get it off the lens plane. Especially for weddings etc. I used to have a Vivitar 285 flash but it bit the dust after 17 years of use. I need to replace my studio strobes because they too have ceased to function.(Speed-o-tron brown line). I was mostly wondering about the flash because it seems that digital cameras have changed the rules on how things are done. Most of the cameras have a pop up flash but there are times when I won't want to use the pop up and use something else.

I use Alien Bees and White Lighning flash units, both are safe with all of my cameras: Oly 35mm, Mamiya TLR, Bronica 645 and Oly E-1. The Oly C5050 has a special built in flash adjustment to trigger off camer self slaved units like the AB and WL units.
For off camera flash, I will use the Olympus bracket or a Seigman unit that I have had for 20 years. You will probably have to go with a Nikon cord and flash should you wish the ttl cpability. Some third party manufacturers may have something that is compatibe, but i do not use Nikon, so I am unable to direct you.

You've gotten some very good advice from the forum. I use the d70 with the Nikon SB800. It's works very well on the shoe but it comes with a plate that will hold it off to the side and fires automatically when you fire the pop up flash. Put it on either side and it gives beautiful ttl flash from the side set off by the popup which fills from the front. The mounting plate also has a tripod thread so you can set it up that way as well. If you have more than one SB800, you can use it on the camera and control all your other flashes from the commander on your camera. It's practically foolproof.
Neil