3) Yes, it needs changed every 10,000 miles if stock, or cleaned at same interval if K&N.
manual calls for 12k change out, they last much longer than that, and actually filter better with more miles. when your mpg goes down, blowing black smoke, and your plugs are carboned up then it is time to change.
the honda requirement does not know in what kind of conditions u ride in.
checkout
www.bobistheoilguy.com air filter section on how long airfilters really last and why not to use a k&n.
I use the stock filter with the epa noise reduction metal screen removed for more airflow. It is an excellent filter material. do a google search on honda oem air filters.
oil filters I use pure one in a larger size PL14459
ditto on fork oil, change it. I use amsoil suspension fluid 10w