25AA320A EEPROM byte write and page write
Well, one address generally hold one byte, so if you write to address 200 then the next byte you can write to address 201 and so on.  

As for what is considered a byte and what is not, generally the write call only accepts bytes so whatever you give it will be converted to a byte.  If the compiler doesn't like that, you will probably get some sort of an error when you compile it.  A byte can be either 0 through 255 or -128 through 127.  

For writing a page, just write 32 bytes.  If you want to use specific page write commands that the chip supports but the library doesn't support, you're out of luck unless you write your own library or find one that does.