“Wexford is proposing the development of a 75,000-square-foot research and development facility,” City Manager Tom Golden said in a Sept. 4 memo to the council. But the vacant HCID parcels have struggled to attract developers with the vision and scope to build out the centrally located and high-profile parcels. It responded to a request for proposal on the three-phased housing-retail LINC project that UMass Lowell sent out more three years ago. “Wexford Development continues to have interest in developing parcel 15 in the Hamilton Canal Innovation District (HCID),” Golden said. Both locations will each add about 300,000-square-foot buildings, about 20 percent of which UMass Lowell will occupy.