Ark reborn will be conflicting with dino overhaul I imagine, considering both of them make significant dino changes (especially that AR changes spawns to AR dinos). You could try playing with the order, however having AR gear/saddles and alphas with non AR dinos isn't likely to be a balanced experience...

You are welcome to do you dino mods however you would like, whichever is "1st" in the mod order will take first priority. So, if you want tameable dinos, you can put it first to have those dinos, and then you could put dino overhaul after if those are the dinos you would prefer in game. Then you could finish up with Ark Reborn if you only wanted the equipment/items.

However you want to do it is your choice. Just keep in mind, that whenever you switch out the order of dino mods, that will clear out any dinos in your server that are being over-ridden. At least, this is usually how it happens. It all depends on the mod really :(