LITTLETON — After a selection committee in March reviewed requests for quotes submitted by three consultant teams and then interviewed each, the Select Board on Monday chose one of them to undertake engineering and architectural services for the first phase of the Riverfront Commons project. “The unanimous selection was the SE Group, which is a combination of architects and engineers,” said Littleton Town Manager Jim Gleason. Also submitting RFQs were Horizons Engineering, of Littleton, and Samyn D’Elia Architects, of Holderness. The Select Board voted 3-0 to accept SE Group as the consulting firm at the negotiated price. The selection committee was made up of representatives of the Littleton River District Redevelopment Commission, the Select Board, the Littleton Conservation Commission, the town manager, and the director of the Littleton Department of Public Works.