WHATCOM — These are the opening dates of the 2017-18 school year for local systems: Tuesday, Aug. 29 — Lynden Christian Schools, Cornerstone Christian School Wednesday, Aug. 30 — Meridian School District, Nooksack Valley School District, Ebenezer Christian School Thursday, Aug. 31— Lynden School District, Mount Baker School District Tuesday, Sept. 5 — Pioneer Meadows…