Assume from the word 'layover'that both flights have been redeemed under the same booking?
Edit: OP did say 'in one booking', my apologies

In this case then yes for lounge access at ICN:
https:/www.cathaypacific.com/cx/en_HK/destinations/lounges/all-lounges-admittance.html

Priority check in & baggage yes too I'd assume
priority boarding no for ICN-HKG