Hmm.
Well, if you have both steering column covers off, look at the aftermarket wiring that's going there.
You should have a bunch of thick wires from the Viper, going to some thick Honda wires---those are for the constant, ignition, accessory, and starter circuits for the remote starter.
They probably also have a smaller white wire running up there to the Honda's negative-trigger parking light wire, and maybe a brown wire going to the horn if they hooked that up.
So, now look at the keyhole where you put your ignition key. There's a black module around the keyhole with two plugs. The XK05 (or any other brand bypass) should be spliced into one of the wires (immobilizer data) at one of those two plugs.
Maybe you can follow the wire down from there. Also, if it helps, the XK05 has the same wire harness as all the other XK modules: brown, red, black, green, orange, purple, PURPLE / white, blue.....maybe something else.
The data wire from the XK05 might not reach all the way up to the steering column, so the installer may have extended it with another piece of wire.
Also, if you look at all the connectors on your Viper brain, I believe that the only two connectors where the wiring would be covered by a black sheath would be the antenna cable, and the data-to-data cable. All other wires are exposed (although the installer may have wrapped them in tape). So, if you can get to the brain, see how many sheath-covered cables are coming out of it.....that might give you an idea of whether or not they used data-to-data.
Some installers might also choose to tape or zip-tie the XK05 right onto the Viper brain, and then extend the neceesary wire(s) to reach the steering column. So try to turn the brain around or look behind it.
As far as your other question.....I haven't used a DB-ALL yet but I'm sure it's fine.
I've mostly used the HONDA-SL-3 as it's inexpensive, and comes in a small bag and therefore takes very little space in my car. (I work on the road, going to car dealerships.)
The ADS TBSLHA is also good. Nicer construction than the Fortin piece, with locking connectors.
The DB-ALL is quite a bit more expensive....I'm not sure if you'll have to fight to get your installer to use it without wanting to charge you.
On the other hand, I think I've heard of people using the XK05 on Honda without trouble.
I guess what I'm trying to say is hopefully your installer is competent enough to troubleshoot his work to determine what is the problem. (Remote starter, car, installation, bypass module---he has to narrow it down.)
If it were me, I'd try to troubleshoot and identify first, so I could fix it right and the customer wouldn't be back.
On the other hand, just the act of changing to another bypass module means he'll have to re-do some of his connections, and by sheer dumb luck might accidentally fix something that wasn't right before.