I mentioned the ADL simply because its cheaper than the BDL, its the exact same action the differences are the BDL has a hinged floor plate, The BDL usually has a better quality finish, but you will probably go matte finish of some kind anyway. The ADL is just the cheapest way into a 700. The PSS, VS, and such models of 700 are much nicer rifles and if cash permits by all means buy the best you can. I started out by purchasing a 700 PSS for $675.00 I then installed a jewell trigger, Krieger match barrel, H-S precision pst25 stock and had the action trued, I basically only have the original action left on the gun, everything else has been upgraded, If I would have started with a $400.00 ADL I could have saved $275.00 and still had the exact same rifle. In short if you plan on building a custom rifle dont buy a more expensive one only to change everything. As far as the questions reguarding the action work and trigger, rather than explaining alot I would reccomend looking at either or both of the following companies websites ROBAR or
HICKS DESIGN (HD RIFLES)
They have both done work for me and are among the best in the buisness. There web sites should give you a good idea of what the different processes are. Good Luck!!!!!!!!!