then, to me, it doesn't get any clearer than this:
http://www.cic.gc.ca/english/resources/tools/temp/work/permit/implied.asp
"R186(u) allows for persons to continue working under the conditions of an expired work permit, as long as they applied for a new work permit before the original work permit expired and have remained in Canada. Once the decision has been made, the client will either have to leave Canada or will continue as a worker who holds a valid work permit."
it doesn't say anything about any exceptions for the type of original work permit, whether it is renewable or not, it clearly states that if "they have applied for a NEW work permit before the original work permit expired" they can "continue working under the conditions of an expired work permit"
so this covers the situation exactly, a new work permit has been applied for, based on the PR application... and the expiring work permit is a PGWP which is an open work permit, my spouse should be able to keep working at the 2 jobs and should also be able to get a new job, as this is following the guideline exactly "the conditions of an expired work permit"