Excluding some elite crafting recipes, the only recipes for armor are vanilla ones. IMHO, it should work the same as other tools; make Wrought Iron Armor, or Aluminum Armor, or Tungsten Armor, etc...

Same goes for Lumberaxes, of which the only one made of non-vanilla materials is the Dark Steel Lumberaxe.

GTCE devs appear to be working towards adding some kind of armors (see for example GregTechCE/GregTech@2af9e1f).

As for the current state of our pack, you also have access to very good armor options from EnderIO and its companion mods such as Dark Steel, End Steel, and Stellar Alloy, which all have nice deterministic enchants. Draconic Evolution and other endgame armors are also available later if you are so inclined.

Regarding lumber axes, these were added as a stopgap when GTCE axes broke in an older version (I believe the relevant issue is this one: GregTechCE/GregTech#862). This has since been fixed, and GT axes should work fine in the pack version if you want alternatives to the lumberaxes, which we just never removed.

GTCE's armor feature I mentioned before seems to have been abandoned.

Given the abundance of armor options already available, and the lack of emphasis on combat in this pack, I think adding new armor isn't really necessary.