HI @PatrickB 

The skis that you mention (Dynafit Speedfit 84) are touring skis, and more specifically, are designed for ski mountaneering missions and be coupled with TLT style bindings, which can switch between "cross-country" and real downhill mode by locking the heel. This stuff is very expensive, and not compatible with any XC bindings. Touring skis don't have traction pattern with the exception of some Voile models. These skis are not waxless in the XC sense, they are designed to be used with the climbing skins that are attached to the bases on the way up and horizontal approach. 

Addressing the questions you asked and some responses above.

1. SNS boots are rarity compared to NNN line. If you really need them, some XC ski resorts may sell used boots, as for some reason they seem to prefer SNS over NNN system.

2. Mounting NNN BC to a regular racing, or recreational resort XC skis could be an overkill. However, it is not uncommon that NNN BC bindings are slightly wider than the ski under the foot. I have (among other things) a pair of Madshus Eon with NNN BC Magnum bindings mounted on them. The base plate of Magnums is I believe, 68 mm and Eon is 62 mm underfoot, and I love this setup, as it fits into the machine-made ski track on the resort (well, after the track gets a bit of the use) and is generally sufficient to ski on up to a foot of the fresh snow. Note that Eon is not the narrowest XC/BC skis on the market, and generally, the skis with the metal edge want to be paired with the NNN BC.

3. I believe that skate skis are pretty narrow and don't have sidecut, which may require a different approach for skiing classic style. 

4. I'd probably switch to NNN system. If plan on venturing outside groomed trails, I'd get something in 62-68 mm underfoot (e.g., Madshus Eon, Madshus Epoch and comparable Fischer models) with NNN BC bindings, preferably manual. They will do just as well on the resort, but will give you an extra capabilities outside. If you already have skis that you like and don't want to invest in a new setup, and the skis you have are narrower than 50-55 mm, I'd probably stick with the regular NNN (they are cheaper and easier to find). Note that NNN BC and NNN are not cross-compatible either way.