I always just assumed Null built their own Logis and the like. Why would they have any impact on Jita trade volume except for toys and resources?

Not that I've ever looked at the trade volume of Scimitars, but I haven't ever seen one outside of an Alliance video. Basilisks tend to be favored for wormholes where shields matter, but only for PvP or lower class WH sleepers. Never seen a Scimitar used for Logi in Highsec or Lowsec that I can recall; not even for station games, but I don't get out much these days.

Guardians are, or were, used fairly often for Incursions as I recall, with a lot of the successful Incursion runners using armor. From other thread, I gather they still do. Most small gang warfare I've seen in Lowsec, (Pirates et al), are using Amarr or Gallente Armor, or they are using Minmatar which are often armor tanked.

The exceptions being Drakes and Falcons for the most part. That is just what I've seen though and it's hard to make a statement that nobody uses anything else anywhere.

Null of course has massive Drake fleets, Mael Fleets, etc.. but those are Null and I don't expect to see Alliance shopping at the local Wal-Mart.

You are quite mistaken, you dont see them because they are on empire alts so they don't get targeted but null sec is not building as much as you'd like to think especailly T2, there's very little T2 production in null sec just due to needing an array of moon goo products and weighing opportuntiy costs.

I think you mean manpower, otherwise that makes little sense. Outsourcing makes sense on manpower mainly. Since building should be fundamentaly easier and cheaper in null, with less barriers of entry.