To the last question both of these parameter work in pairs. So no to the third entry. If you add a third just make it the same as the ASM one and your done.
Your parameters look OK to me, but I cannot see your ASM
Yes, the other way around for the standby.
See E10642-03 under the section "Using the DB_FILE_NAME_CONVERT to Generate Names for Non-OMF or ASM Datafiles" fro more information.
When primary is on non-asm and standby is on ASM, then the first string should always belongs to primary and then the next string of course belongs to standby.. If your data files situated in multiple locations, then you can add more as required.
An example here below, you can mention "+DATA" instead of "+DATA/prodDB" if you are using OMF and Oracle takes the directory based on the DB_UNIQUE_NAME you set, So disk group can do your job.
The same applicable to LOG_FILE_NAME_CONVERT as well.
Some link for you to go through.