2015 Chevrolet Express 3500, Viper Security

I am interested in installing a viper proximity alarm system in my chevy and it requires a starter kill switch relay when engaging the alarm. So Im looking for the best location to access directly the starter signal wire to install that relay switch, preferably close to the passenger side where the BCM is located. I see theres a couple of points on the BCM for Ignition.
2 PK Off/Run/Crank Ignition Voltage
4 WH Off/Run/Crank Ignition Voltage
14 PK Run/Crank Ignition 1 Voltage
And theoretically pins 2 - 4 are the "secondary starter
Second Starter pink (r-code), white (5V ref) (Tech Doc 1605) +9600 ohms ignition switch or BCM under pass dash, green plug, pins 2, 4" from some guys post on here regarding a 2016 on this subject, which i might add has been incredibly informative. I just would prefer a more direct connection without potential interference from other connections delivering power to the starter for this.
My question,
Is this counter intuitive? Trying to install an additional security system along side the GM standard passkey 3? Will it interfere with any stock anti theift system installed already?
Does that starter signal wire that connects to the underhood fuse box, 56 pin plug, pin E1, run through somewhere close the the BCM?
Anyone who has done this install before willing to offer some advice?

Eliminate the starter kill from the equation, your PK3 is sufficient.

Thank you for the suggestion, and I am considering it.

My van also came with RKE, so I am thinking this whole viper install might just be redundant, but I would prefer the viper as I am more comfortable with its system. The proximity alarm and theoretical comfort closure using aux1 sounds ideal.

Currently, I'm under the impression there is no real alarm system installed to alert me of potential theift or vandalism.

I value outside opinions, especially from experienced technicians, and Im open to your advice. Really, any information regarding the PK3 system or Viper security install is appreciated.

Ive wrapped my head around the wires and where they should go, even the starter (as long as it won't interfere with the PK3) but Im unsure of the best Instant trigger input wire, I've read hood pin or dome light but the dome light may cause an instant trigger on exit.

Also, does anyone know if connecting (-) 200mA TRUNK / AUX 1 OUTPUT (Channel 2)
Or
(-) 200mA AUX 2 OUTPUT (Channel 3)
To a master power windows switch would work to close windows?

The Aux 1-2 is probably another wire to eliminate from the equation considering there is no trunk and I have no idea of any other Aux options besides windows.

What would you do in my situation? Contractor with all my tools in the van. previously considered 1000 watt capacitors for an e-250, purely precautionary...