Hi guys, right now I'm buying parts for my g37's valve cover job. I watched a couple videos on youtube like

this TRQ one:
and this one from DIY garage nation:

both of them take the entire plenum off and keep both throttle bodies attached. Chatgpt said I should remove the throttle bodies from the plenum, because apparently coolant hoses go through the throttle bodies? So if disconnect the hoses, I introduce air into the cooling system and I have to bleed it? Sorry for my lack of knowledge in engines but is that true? Is it okay to remove the plenum with the throttle bodies attached or is it a bettter practice to disconnect the throttle bodies from the plenum?

On a side note, this is the stuff that I have in my cart so far. Is there anything that I still need to buy?
Right now I have these items in my cart:
oem throttle body to plenum gasket -- for if I need to disconnect the throttle bodies from plenum
z1 ignition coil pack
nissan rtv
valve cover gasket kit -- both sides valve covers, both sides valve cover gaskets, 2 spark plug tube seal gaskets
I already did spark plugs 5k miles ago so I don't think I need that.

If anyone is willing to help by providing answers, I would really appreciate it!!