Lacking plain hypo, I'd try plain Kodak Fixer, the powder, which is a sodium thiosulfate based fixer. The problem isn't the hardener per se, so much as how quickly the fixer acts, and then it might depend on what the hardener is, how acidic the solution, and other factors.
The trick is, the print needs to be fixed completely without bleaching it right off the page. If it isn't fixed completely, you'll have undeveloped, unfixed silver halide in the emulsion that will print out as the print is exposed to light, leaving brown marks on the print. The prewash before toning is also important in preventing this problem. Before toning, the print should be rinsed until it stops releasing a milky residue.
Kodak Rapid Fixer even without the hardener I think is going to bleach an albumen print too quickly, and will be harder to control, and the same would be true of other ammonium thiosulfate based fixers, which are generally sold as liquids.
Even with a sodium thiosulfate based fixer, you'll get some bleaching and color change, and you also get bleaching and color change in the toner, which is why the exposed print needs to look about two stops overexposed before toning and fixing.
Also, look up "The Chemistry Store" to see if they can ship you some hypo faster than the other photo suppliers.