If I'm reading the new FAQ correctly, a HWK with Bossk and a TLT now will only trigger Bossk if both TLT attacks miss. Does that sound right?

Yes, exactly that. A lot of stuff are now "less good"

I guess the bigger question is:

For weapons like TLT and Cluster Missile, do they have to get the same result on both attacks to trigger after attack effects that only happen when hitting or missing?

I guess the bigger question is:

For weapons like TLT and Cluster Missile, do they have to get the same result on both attacks to trigger after attack effects that only happen when hitting or missing?

Basic Boolean math say that if you did not miss then you hit...

It is impossible to have not missed and not hit, this is not a state that exist in the game