elk, cat5, and doorstrike questions....

OK, I'll stab at #3.

I used a wiegand keypad outside hooked to the wiegand (prox) reader input of an Elk keypad inside. I happened to setup the Elk so the correct outside code opened the door and also disarmed the system, but you could separate those functions by how you setup the Elk configuration.

For the main lock, you use a regular lockset and an electric strike powered by a relay. This can be output 3 or a relay like the Elk-912 hooked to any output, including the output on the indoor Elk keypad. With this setup, you just use the handle to leave. If the power fails, use the key to enter.

Can't speak from experience on the deadbolt, but once you've located an appropriate electrically controlled one, you can do pretty much whatever you'd like with the Elk.

See my "calculator" page to help setup the wiegand user id for the Elk and for a link to the outdoor keypad I used. The strike I used was from RCI
I used CAT5E stranded in my house almost exclusively. I like stranded because it is more flexible, which is important inside of a small keypad enclosure. Some people claim stranded is harder to terminate, but I have never had an issue. CAT6 is fine too, but right now there is no application that requires it. Gigabit will run over CAT5E fine. But no matter what, I would stay away from shielded. You are just asking for trouble when terminating there. The only time you would need shielded is if you plan on running HDMI over it using those HDMI to CAT5 converters. And I am still skeptical that shielded helps there.

As for the deadbolt etc, I would go with the weigand approach vs. the powerbolt hacking. With the powerbolt you have to get the wires into the door. With the other approach, you need to power the electric strike and deadbolt separately, not via the elks power supply. And the deadbolts I have seen retract into the doorframe, not the door. So there is no manual operation, meaning you probably need fail safe vs. fail secure, for the deadbolt, so you can escape if there is a fire. The electric strike would be fail secure as you can just turn the door handle manually. Another option to look at here are the magnetic type locks.
Here's a couple electric deadbolts to consider:


Note that these are designed to lock upon sensing the door closing. So you'd want a "push to exit" button on the inside.

Now the Seco has a "fail secure" model with a manual lock/unlock. I'd defer to the Pros to know if this would meet code from a life safety/fire perspective.