Does your LHBS have Crystal 10L? It's the same thing as Caramel 10L. If not, you could bump it up to Caramel or Crystal 20L and just lower the amount. It won't make a huge difference. You could also try Carahell malt if they carry it.
Caravienne can be replaced with Crystal 20L
There is no replacement for wheat. I suggest mini-mashing, or putting the recipe aside until you can mash.
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