H1-B extension and F2 COS

My labor cert is with BALCA, I got one ext after 6 years in H1-B, now I applied for another ext as case is still with BALCA, My H1-B expires on 8/15/15,I was wondering if I can also apply for F2, as wife is on OPT-F1, so if H1-B gets denied, always can get F2 , so can still be in status, can I have 2 applications at USCIS, once I get one, can then withdraw the other, is that possible, TIA