Obama carried NJ by almost 20 in 2012 due to Hurricane Sandy. It wouldn't surprise me to see Biden match or exceed that - and if Murphy allows universal mail ballots like the primary this could get ugly for the R congressional candidates.
Yes but polls like these which show Biden in a dead heat or worse (after the normal adjustments to internals) suggest that South Jersey isn't going to be one of these 'snap back' regions. It suggests that Biden's going to dominate in North Jersey and get his 20 points in the suburbs like Morris.