How much time to transfer from USA flight to a China flight at HKIA?

Am arriving T1 on a United flight from USA and then to catch a Cathay Dragon flight to Guilin? I will have a checked bag to pick up after immigration. My tickets are separate.
Will I have to go out of Security to check bag with Cathay, then get re-screened for immigration and security?

I have not yet booked my HK to China flight and want to pick a flight that gives myself enough time.

Thank you!
PS -- I will have lounge access from my United flyer membership, none with Cathay. Will I be allowed to use the Star Alliance lounge with my arriving flight boarding pass?