GEWURZTRAMINER: 2 exceptional matches are Gruyere and Emmental. FWIW, from my tastings I've never found the classic regional match of Gewurztraminer and Munster to be very interesting, but try it yourself.
SYRAH: An incredibly cheese-friendly wine, you might better ask which wines don't match with it. But among the best IMO are: Appenzeller, Beaufort Savoyard, Chevre, Comte, Aged Gouda, Gruyere, Montasio Mezzano, Parmesan Reggiano, Roncal, and perhaps the very best... Pecorino Toscano and especially Pecorino Stagianato. I could list another ten cheeses that match fairly well if that gives you an idea of the versatility of syrah and great cheeses.
Those are pretty different wines so very wine-friendly cheeses such as Manchego, Gruyere, Tete de Moine, Reggiano, and Brebiou would fit.
A mild, buttery blue such as Danablu, Blue Castello, or Gorgonzola Dolcelatte would be nice with the Gewurz and maybe with the Syrah depending on the style.
I think finding one cheese to pair with both wines might be tough but if you are looking for a cheese for each wines this is what I would reccomend:
Gewurztraminer- soft and stinky so something like Munster, (from Alsace) Epoisses or L' Pie d' Angloys.
Syrah- hard and salty. Piave, Parm, Manchego or Petit Basque.