He has signed for the Magpies' 2013 and 2014 seasons.
"Ged has a massive leadership role with the Rebels and I'm sure he will bring it to our environment. He is coming back to New Zealand with the aim of making the All Blacks and is a motivated beast," Philpott said.
"He told me he has learned a lot in the three seasons he has been with the Rebels and is playing the best footy of his life."
Philpott said Robinson hoped to score a Super Rugby contract with a New Zealand team for 2014 and in the unlikelihood of him not succeeding, the Rebels would welcome him back.
"I'm really looking forward to returning to New Zealand and playing ITM Cup for Hawke's Bay. They are keen for success and play a brand of rugby that I enjoy," Robinson said.
Lahiff, 23, has been plying his trade for London Irish in the English Premiership since 2011 and through his father is Australian qualified. He is a strong scrummager who can play on both sides of the scrum and is a damaging ball carrier and defender who has already been labelled a 2014 Wallaby by British rugby critics.
One of Lahiff's biggest claims to fame was keeping former All Black and London Irish captain Clarke Dermody out of the match 22 during the 2011-12 season.
"I'm really excited to be joining Hawke's Bay. They are obviously a proud union with high expectations and I want to be part of that.
"I have played a lot of rugby with former Magpie Bryn Evans and he speaks really highly of Hawke's Bay. The ITM Cup is a great standard of rugby and it has always been something I have wanted to experience," Lahiff said.
Philpott said he was aiming for Lahiff to play tighthead for the Bay with Crusaders Knights prop Adrian Barone the loosehead.
Havelock North's Brendon Edmonds is another who can play both sides and with the Taradale pair of Jody Allen and Ziggy Fisiihoi there will be depth.
Former Crusaders prop Pete Borlase won't be returning to the Magpies after collecting a career-ending injury.
Borlase is reported to be coaching in Colorado.
Robinson and Hurricanes hooker Ash Dixon will battle for the starting rake's role. Robinson will arrive in the Bay at the end of July in time for the Magpies' final pre-season game.
Lahiff, who can bench press 180kg and squat 250kg, will arrive at the end of next month.
Philpott said the pair have yet to be allocated to a club.