It's impossible to predict how the NHL is going to handle the draft or the rest of the season. I wouldn't necessarily count on them doing the right thing whatever you think that might be.
Draft order is based on reg season results, so I'd be annoyed if they changed the rules in any substantial way. The rules didn't change the year we had a partial lockout, so they shouldn't change because of a shortened season even if the playoffs are cancelled.
To me, you change it to be based off pts % assuming all teams haven't played an equal number of games (which seems inevitable), maybe you ignore the playoff seeding and just cut off at only the bottom 15 teams league wide are eligible.
Will the NHL do that though? idk.