Keep an eye on bikes direct and be very thorough to find all their deals. In September I got a 2010 29er Motobecane for $350 that came with Avid BB5, WTB FX28 rims, decent WTB tires, Rock Shox Dart 3, Shimano XT rear derailleur, Deore shifters/ front derailleur, WTB speed V saddle, truvativ cranks. Basically, the parts alone were worth as much if not more than the bike as a whole. This kind of a deal is hard to find though, and really depends on old stock and the time of the year. You may be able to find a really if you are patient and know what you are looking for (same goes for buying used).

Those bikes you found are not bad bikes, and if you stick with what you listed as wanting to do they should be bike enough for you. With so much smooth path riding you would probably want to switch the tires out to something that rolls a little better on flat/hard surfaces. However, if you ever want to do real mountain biking those bikes wouldn't last too long without receiving very regular maintenance.

Edit: oh yea BD stems suck really bad. I found the grips/pedals were actually tolerable, but the stem was a huge, long, weirdly angled, clunky thing.