Personally, I don't think these are like-for-like comparisons. T Couchman is a middle who averages 60 minutes, Laban is an edge backrower who is lucky to get 20 under our rotation (he wasn't even used last week). Better comparison for T Couchman would probably be Demi and I'd definitely take Demi over him. Conversely Laban's appropriate comparison is probably Dylan Egan or Hamish Stewart and I'd take him over both of them.
Liddle and Healey are also at different stages of development. Liddle has played 100+ games over almost 10 years and has very little additional upside. Healey is basically in his first full year of first grade and has a lot more growth in him. Better hooking comparison across the league is probably an Owen Pattie/Riley Smith.