Our kids haven't needed their residency cards for either VDMIS (last year) or Los Pininos (this year.) Which, I might add, is a good thing since we've been waiting, waiting, waiting, ahh, did I mention waiting? for 10 months to get through the process. We are technically legal but stupid things like the cedula plastic running out and then the printing machine breaking, and one of our kids' applications being separated from the 5 of us...all have delayed it. By the time we get them, we'll have to renew them.
I think that school may have a diff set of regs...maybe if you give them a copy of the passport and tell them "I'm in the process." Also, I think it depends on what grade. The 8th grade and above kids have to take the Nationally-mandated exams and I seem to recall something about them needing Cedula #s for that. Anyone verify?