Given the infrastructure issues in TXL, I would take the itinerary with more connection time. I also think that your assessment of FRA being a zoo is overblown. FRA is a totally logical airport if you just follow the signs.
In FRA he would need to switch terminals (from T1 to T2) as LH arrives in T1 A concourse and CX leaves from T2 (E concourse). Given that he is leaving the Schengen zone in FRA, he would need to go through passport control, but can probably avoid a security check if he takes the Skyline train from the A/Z departure. However, since LH and CX cooperate he could probably check his baggage through from TXL to HKG/ICN.
Last edited by SunshineStay; Jul 17, 2019 at 5:48 am
Reason: Correction re security check