The Mauser is Chilean, looks somewhat like a German M98 of WWII, but here you can see some photos of details of the similar Chilean 95 Mausers. The 98 had a bigger receiver ring, and a safety lug halfway down the bolt that is a failsafe in case the gun ruptures. Yours almost certainly wasn't in WWII.

The Japanese rifle is a 6.5 Arisaka, obviously a war trophy because the chrysanthemum stamp on the receiver is intact: ones impounded and sold as surplus later had that ground off. I don't know Japanese, can't help you with the bayonet. But that looks like active rust on it: you should scrub it off lightly with some fine steel wool and apply a little wax to keep it from real corrosion.

I should mention that it's a very common leap to assume that a gun owned by a veteran is the gun used/acquired by the veteran in a war. For example, there have been a lot of Kentucky rifles circa 1830 that have been proudly displayed by a family as the rifle their great-great-great grandfather carried in the American Revolution. It wasn't: it was the last one he owned when he died in 1837, and eventually family tradition just connected the two.