I've done these mostly with the FLCAN, the FLDL1, and long ago, the old 455J I think it was called back then. So I might be a little off about the DBALL information but I'll try.
1: That would be to control the car's door locks through the data bus in the car.
2: Readyremote.com should have the resistance value you need. The Avital white (with the jumper installed in the negative trigger position) will go through a resistor and to the car's parking light wire.
Personally, I just pop out the car's parking light relay (just above the fuses), test for the straight negative-trigger wire at the relay, and tap my remote starter's parking light wire in there. This way, no resistor needed.
NOTE: Don't try to power up the positive parking light wire in this car. Stuff will break.
3: Two square connectors above the fuse box. In the left of the two connectors, gray/orange is horn. (Should be in steering column too; I never looked there.) And you'll be looking for a negative-trigger wire; it's before the OEM horn relay.
4: I've always used one of the 10mm bolts holding the big metal thing on around the ignition wires. A lot of people would recommend going down to the driver's kick panel and directly to body metal. In either case, no need to go directly to the battery for ground.
5: Haven't used the DBALL, but "set to positive" they mean which way you're supposed to put in the little jumper that's taped to the Avital brain.
But your two options are essentially this: Configure Avital for positive parking lights, connect that to the DBALL, and then the DBALL does you the favor of handling the resistance for you in the car.......or, skip all that (especially if not using DBALL) and wire up the Avital to the car directly to control the lights, as in #2 above.
6: Shouldn't need to connect these to anything if not using a bypass module.
7: That's to trigger extra relays if you have a car that has several separate accessory wires. Shouldn't need it for your installation.
8: That sounds right.
9: This is the part that'll surprise you.......your car doesn't have any easy-to-connect doorlock wires anywhere inside the car.
There are some diagrams if you do a search....fish wires into both front doors, wire up two relays in each front door.....lots and lots of labor. I've never done it myself, and I wouldn't want to.
So basically, just because you don't have the gray Sentry Key, you need a module anyway just to do the locks.
If you can find an old-stock 455J you might find it cheap. Or else that DBALL, FLCAN, FLDL1, EVOALL.
NOTE: Modern bypasses require that they be programmed with the correct firmware for the car being worked on. If this is something you're going to buy online, make sure you find a seller who knows what he/she's talking about and get a module with your firmware already on it.
10: Yes. On the Grand Cherokee, you can actually give the brake pedal switch a slight twist and it comes out to make the wire easy to get at.
NOTE: These brake switches are fragile. I had one come apart in my hands once. They're cheap at AutoZone and usually in stock.
11: Not sure. You might try searching the forum and see if someone else has tried it before.