Yes, as Daryls personality and traits wouldn't urge him to think and piece clues together. He wouldn't even be so suspicious.
I'm in the process of creating the second character, I may not even choose a second one at all. But when using Daryl having a second character is so good because they're normally better with people.
Using the same character so much can be a little tedious, but I don't mind as Daryl gets fun. Just a second character normally helps with variety.
Would the NCR hire an assassin? Just someone who would kill someone important or not important for a sum of money. If possible, I'd like to have someone like that.