I posted the same question a year or so back to Dan Checkoway who has everything you plan to run and he indicates no problems at all. Randy Debauw's RV-10 has similar setup with out problems. Here is my setup although not flown yet it seems to be interference free so far.
Wire size for your position lights needs to be calc'd for distance and load, #18 most likely but double check it. Van's has a table in the builders manual.
I have TT A/P servo, pitot heat, tip strobes, position lights, Archer Com one side Archer Nav/MKRBCN the other. I used RG-400 for the antennas, #14 for the pitot heat #18 for position, shielded strobe cable from Van's for the strobes, #16 for the landing/taxi light. Terminate to the unit the shields for the strobes at the source not the strobe lights. I grounded each electrical device at the point of operation, not back to the single point on the firewall. All fo the Aerolectric info says this setup is OK, two builders have confirmed thiers works OK as well.
It depends on how you want to run the whelen lights, if you want independent control you will need a power lead for each, if you want them to operate together one power lead, just make sure you consider the extra amps drawn to calc the size of the single.
Looky here for install and wiring info for Whelen:
http://whelen.com/aviation/Avserman.pdf