Do I Have To Serve Filings on Opposing Counsel?

Not if you use the Court’s ECF system and opposing counsel is a registered user of ECF:  “Delivery of the notice of electronic filing that is automatically generated by ECF constitutes service under Fed. R. Civ. P. 5(b)(2)(E) on each party who is a registered user of ECF.”  See L.R. 5.1(d).