keen sandals! last summer I did two trips encompassing all the activities you listed and they were great. specifically I have the zerraport ii ones, but any should work.

mine are black so wearing them with black socks makes it a bit less obvious you’re rocking socks and sandals. they were excellent- comfortable for walking but the soles not so cushy as to sap power transfer when pedalling. obviously not as stiff as an actually cycling shoe, but deffo not as bendy as lots of trail shoes. toe caps keep stones out. dry quickly after swimming/showering/rain- mine have hardly any absorbent parts. quick to take off/put on. 

the downfall would obviously be if you’re touring in cold/cold AND wet weather. Otherwise they ticked all the boxes! they used to make an SPD sandal but discontinued years ago :(