all steps to start thinking/implementing a cold storage system are the right way to do it. You take ownership of your funds.
In my opinion security is always a trade-off. How much are you willing to invest, to protect assets?
My two cents in this discussion: think about the value to protect, and maybe take some analogies of real world:
small values are in my purse (wallet), with several bills and coins
monthly values are at my bank, cause I trust them, and they have high walls around "my money" to protect it from being stolen
large/huge values (e.g. pension funds): I (might) trust a government, which has an army, to protect against neighbours coming in...
So the higher the value, the more needs to be invested into security.
Cold storage (any system, even hardware wallets) is the best way in getting started, and then based on the level of comfort and willingness many options come into the game. Operating system (you provided a good set, I'd like to add a BSD type OS), transfer methods (USB, Camera, sound ?), and finally wallets on top... maybe the next layer is how to protect your room or building against electro-magnetic fields. All a question of personal paranoia