re: What kind of hand saw for this job?

Looks good Brian. You certainly jumped into the deep end with having to chop giant angled mortises. Personally, I’d pin the tenons, it’s good insurance if you get a bit of water wicking into the joint and glue failure. I don’t use anything special to pin tenons; I’ve whittled square oak pegs into a rough round shape, or even simple dowels would work.