In general, yes, most "downhill" (ie fixed heel) skis can be used for telemark skiing, with the obvious exception of a "system" ski which comes from the factory with alpine bindings installed on proprietary mounting hardware.
A related and less obvious issue is the plate on alpine race skis; even if you can mount a telemark binding, these might make it more difficult to flex the ski for someone new to telemark and you would want a pretty active (stiff) tele binding. Coincidentally I figured this out the hard way on some similar vintage Dynastars as the Speed 63 -- had good success with a pretty active binding (Burnt Mtn Spike XT) on a Dynastar SkiCross 10 with plates, but less active 7tm Power on Dynastar Omecarve 10 was nearly unskiable.
As to your last questipn, "traditional 77mm [sic] boot and bindings versus the new step in bindings and boots" - conventional wisdom if you're starting out with a limited budget and not certain you'll stick with it is find a cheap pair of 75mm (not 77mm) boots that fit you well and go from there. In the unlikely event you find a good deal on NTN boots that fit [i.e. the "new step in" variety] , no harm starting out on NTN gear; it may cost a bit more but if you stick with tele you'll like it and if you don't you'll have an easier time selling it.
Better and more detailed answers here: http://www.epicski.com/t/143214/craig-dosties-tele-gear-for-newbies-october-2015