Since the wood only contributes 12% to the overall power of the bow, pick the prettiest wood, especially if you plan on using at least one piece of clear glass. If your yellow birch is the darker heartwood, you might go with some lams of that and some of the maple, for the color variation when seen on edge.
I build bendy-handle bows (recurves and flatbows both), so can't advise you on riser construction.