Dawood can be easily killed with a boat(along with shah) Maelstrom can be killed via poison,The twins for saso are some of the worst targets,alng with tyson willams,and colorado in general.Hitman 3 has very few hard targets,but royce might be the hardest out of the ones you listed
Oh why?
Update on my last comment i got the expansion pass :),Imma work thru the haven and bank challenge pages as i go thru them >:)
Im doing fine for now,trying to grind out some money for that Expansion pass on Hitman 2 during the steam sale :) also working on making some pages for those challenges