To add the break lines back into the terrain, i tried using the "add features" circled in red in the following screen shot.
this is what the terrain looks like immediately after creating the merged complex terrain. (notice the top of bank and toe of slope break lines are excluded)
this is what the terrain looks like after trying to add those (2) excluded break lines (notice the curb, eop, and walk break lines are now excluded from the terrain while the top of bank and toe of slope lines were added)
more and more break lines keep getting excluded as i try to re-add the lines. this wouldn't be to bad of an issue if i wasn't dealing with 2 more miles of roadway topo and intersections.
as for the terrain rules, if i want the terrain to maintain the edits that i have made to it, i will have to keep the rules "de-activated"?
and if down the road more topo/survey is added to the basemap, i will have to re-activate the rules to include the new survey into the terrain and i will have to re-do all edits i had done previosuly?