Might as well start collecting these here. Per Eater Boston, Cathedral Station is set to open in May in the old Red Fez space, with the former Fritz folks doing an LGBT-friendly sports bar / pub there.
Other openings Eater thinks are slated for a May include:
Causeway BBQ, in the old Penalty Box space near TD Garden
Crave - Mad For Chicken, a Korean fried chicken joint in the former Enso Sushi space at the edge of Chinatown
Liquid Art House, the art gallery/restaurant with Rachel Klein as chef, on Arlington St near the Pike in Back Bay
Lulu's, with its very eclectic menu, in Allston's old Cafe Brazil space
Mike's Pastry #2, in Harvard Square
Sa Pa #2, in Cleveland Circle
Totto Ramen (!) in Allston near the TiTS.