The Iron will play in League Two this season for the first time since 2005, but the capture of defender Dawson and striker Iwelumo, plus midfielder Michael Collins' decision to sign a new deal, has helped lift the mood at Glanford Park.
"It's been great and refreshing to see the likes of Andy Dawson and big Chris coming in," Laws told the club's official website.
"But I think that the fact we've worked with them has helped the matter because they know how we work and I think I can get the best out of them as well.
"It's helped the matter, no question about it, but I'm delighted to say that because I thought we'd be dragging our heels.
"To get the acquisitions in and with Collins signing it shows we mean business in terms of bringing in good quality."
Scunthorpe, who have also signed Gainsborough Trinity pair Terry Hawkridge and Luke Waterfall, have offered Iwelumo a one-year deal following his release from Watford, while Dawson returns to the club he left 10 years ago following his release from Hull.
Left-back Dawson has also signed a 12-month contract.