GMCSHEA - hi, I'll agree with JOED that any of the wire types you named would suffice. There shouldn't be enough of a difference in the gauges to affect the line quality, unless you're going to add enough devices to the line to come close to the maximum REN rating. (REN - Ringer Equivalence Number, which will be listed on the label of each phone, answering machine, Caller ID box, etc. Most TelCos say not to exceed 5.0 for the total REN.)
As far as running 3 lines outside to the network junction box or not - where do you prefer to do the troubleshooting work at? Since you're running the wires yourself, you're not planning to pay the TelCo an extra fee each month for an "on-call maintenance" policy where they'd maintain the lines all the way to the phone instrument. So, if you needed to check out a problem, would you rather crawl into a crawlspace or would you prefer to stand by the network junction box? (Which you'd normally have to start at anyway...most of them have a place to plug in a known working phone to check for a dial tone. If you have a dial tone there, then the outlet inside the house or the wiring from the network junction box to the outlet is bad...if there's no dial tone at the network junction box, it's a TelCo problem and you have to call them to report it.)
Are you replacing the old lines "just because" or are you having problems with them? You might find it dificult to remove the old wiring if it's been stapled to the studwork inside the walls, so the saying, "if it isn't broke, don't fix it" comes to mind.
I hope this helps you decide which way to proceed. Good luck! Jim D/Heathsville, VA