Like the new dino colors, the boots, tek stegos, etc. Are they automatically added or do we have to do something special for it?

Haven't seen a tek stego yet but the amount of purple and dark blue parasaurs we saw in ours last night was intense. So i think we're good

if you hit the button for the event in your settings it should patch on restart, you'll notice dirt mounds with bones or items in the loot right away if activated. I tamed 2 Tek stegos on Shigo islands so yes it does work even on modded maps.