They won't upgrade you ahead of time unless you split the reservation because there will be only 1 seat but two people on your PNR.

If there really are just 4 people on the list, they'll likely ask you at the gate if you are willing to split your reservation to upgrade 1 person (you).

However if a 5th person is added to the list before then, the system will skip the 2 of you (because there is only one seat and there are two people on your PNR) and upgrade #5 on the list.

The safest bet would be splitting your friend off your PNR