Thanx. Being a Western Oklahoma Geek, I'll always try to reduce things to the simplest level (science?) . There's a LOT of viscosity data available online, all of which show seed oils roughly the same at room temperature. Canola is thickest, EVO is "mid range". Then there's a gap after which Almond, Peanut and Walnut are very close to Pecan Oil - the least. Roughly the same relationships hold regarding "substance internal molecular friction" (again - roughly - lubricity). As it heads toward becoming cold, Canola again leads the pack, becoming "sticky" rather rapidly.
My thought is: All of this backs your formula as elegant. Leather is a relatively dense collection of fibers rubbing together when moved. I think that as whatever seed oil is used reduces viscosity and internal friction of lubricants (cocoa butter, lanolin) as they "penetrate" (get into and between fibers) resulting in it beng more supple, and therefore - "conditioned".
Then as the seed oils degrade or evaporate, additional "conditioning" is needed.
Furthermore, almost all of the MSDS sheets I can find of the common "conditioners" show significant (almost shocking) amounts of petroleum products in their formulae. Petroleum products (mineral oil, paraffin, petroleum distillate etc.) will chase moisture and natural oils from whatever they encounter. That will wick lubricants OUT of the leather, making it eventually crack, rot or degrade in some fashion.