Book a one-way reservation that the account owner AND the friend travel on the same itinerary, same PNR. Do the same on either AA or AS account - both are on one-way system therefore it makes things really simple and easy.
As long as the account owner is also traveling on the same PNR, you should be fine on that. You could mention to the agent that is "me and my friend" traveling together and ask the agent to notate the reservation accordingly but it is not necessary.
Otherwise you are thinking way too much.
The hotel part does not need to be mentioned anywhere, including here. It is strictly your private matter.