I am very familiar with HKIA as I live in HK, but have never done that connection. However, it should be a breeze. UO is a semi-LCC but a good airline (even nice lounge). You can do internet checkin and get your BP 36 hours before the flight. When arriving in HK, just go through a transit point (e.g. E1) to access the departure level. They are a couple of them and are indicated. You will need to show your UO BP (the eticket will probably be sufficient). Then go to the gate.
Terminal 2 is only a checkin terminal, all flights depart/arrive from T1. It would be stupid to exit T1 , then go to T2 then go back to T1. BTW, UO is moving its checkin operations to T1 as of June 28. But that should not be relevant to you as you will not need to clear immigrations and go landside.
From the moment you debark 45min should be amply sufficient. The only risk you have is if the KL flight is delayed as you are on two different tickets.