Hi KT CountMagnus,
When you place an armor in any slot, it is moved there. This means you are unable to use a single piece of armor for both civilian and combat outfit.
As for the Patreon, you only get the rewards for the month you purchase it. So in this case only January. The pictures and info are updated before the month ends and will continue to 2 months at a time, to give a better idea of what kind of items are included in the Patreon tiers.