Hello Ed,
I'm a long way from APTC, and don't know their wares, but will offer a couple of thoughts because I do use Japanese saws.
That big Anahiki looks like an extremely useful saw to have. My experience has been that a big crosscut saw in the 400mm range is the very thing for cutting large boards to rough length before you start the planing/wood preparation sequence. My only reservation has to do with their description of the all-purpose toothing, which triggers a large dose of skepticism about tools that do multiple things. Nevertheless, I still think it's a good risk, if no one here has direct experience to offer on that saw.
You asked about APTC's ryoba offerings....I think the largest they offer is a 240mm ryoba. All saws are useful for something, but I think you will find the 240 a little too large for most joinery--excepting largish tenons--and too small for crosscutting boards to length, unless they are in the 3" to 4" width range. For crosscutting 6"+ boards to length, a 270 or 300mm saw is most useful. For joinery, most will find a rip dozuki most useful for dovetails and small tenons, and a 210 or 240 cross dozuki most useful for shoulder cuts on tenons. If you're good, you can make a 210mm ryoba do nearly all joinery cuts--if you're good. Gyokucho makes a 300mm ryoba that would be useful for crosscutting to length.
In the US, there are a couple of guys who recondition vintage western saws which they sell on ebay. But they have developed a following, so there's no bargain to be had, even before you pay for shipping from Oregon. For usable vintage western saws, one thought that comes to mind is a lady named ALF who used to post here, who might be able to point you to a good saw. May be worth an inquiry.
Wiley