After all three featured in United's opening pre-season fixture last weekend, White has insisted that McDermott's additions will add quality to key areas of the squad.
He told the club's official website: "I think they all bring something unique to the team.
"Matt [Smith] is obviously big and strong, holds the ball up well and is great in the air. Noel [Hunt] has got a great spring, he has been around, he has been there and done it and brings that experience into the squad.
"And obviously Luke [Murphy] is great on the ball in midfield, he can keep the ball and create chances. I think all the additions that we have got so far have been very positive."
Hunt and Smith were both among the goals in a 5-0 success against Farsley on Saturday, with United's pre-season preparations now focused on a tour of Slovenia.