It seems to me like you're not quite sure what || and && actually do
The || is an OR operand
ie: if (myfriend !isin %nick) OR (fishbot !isin %nick)
If EITHER of these is true, then the statement comes back as True

The && is an AND operand
ie: if (myfriend !isin %nick) OR (fishbot !isin %nick)
If BOTH of these are true, then the statement comes back as True