That's actually one of the biggest myths ever created. Lebanon Valley's last year in the NE was in 2003-04. They hosted a first round playoff game:
http://www.collegehockeystats.net/0304/boxes/mlvcsuf1.f28. The Northeast went to a pre-determined site for a semifinal/final (Matthews Arena), which was decided long before LVC finished second in the NE regular season that year.
Not sure about that one, either. The 1997-98 season was the last season of the old North/Central/South league. The league alignment was as follows:
NORTH: Fitchburg State, Johnson & Wales (first-year program), Worcester State, Plymouth State, Framingham State, Curry, Nichols, Roger Williams, Salve Regina (first-year program).
CENTRAL: St. Michael's, UMass Dartmouth, Bentley, Southern New Hampshire (then NH College), Assumption, Tufts, Suffolk, Stonehill
SOUTH: Wentworth, Skidmore, Iona, Villanova, Western New England, Fairfield, Quinnipiac, Sacred Heart
Bentley, Quinnipiac, Fairfield, Iona, and Sacred Heart all went D-I starting with the 1998-99 season; Villanova and Roger Williams dropped hockey. Skidmore moved to the East.
The 1998-99 season was the first season of the Northeast, with the league lineup as follows: UMass Dartmouth, Fitchburg State, St. Michael's, Wentworth, Southern NH, Worcester State, Johnson & Wales, Framingham State, Assumption, Plymouth State, Tufts, Curry, Nichols, Suffolk, Western New England, Stonehill, Lebanon Valley, Salve Regina
Southern NH and St. Mike's played each other in the final Division II National Championship game that year.
St. Michael's and Tufts continued to play in the Northeast until the end of the 2000-01. Tufts actually was the #1 seed for the 2001 tournament, but was upset by Salve Regina in the first round. LVC won the league, beating Wentworth at Wentworth. St. Michael's began play in the ECAC East in 2001-02 (
http://www.collegehockeystats.net/0102/schedules/stmm), while Tufts began playing in the NESCAC for hockey in 01-02.