Item A is not really a postal item, but an offering envelope. It has $8 on the outside. I was hoping to find $8 on the inside, but no luck.
Item B is a letter form USPS stating item ordered is not avaiable and a replacement item was sent.
Item C is Postage Due 10c stamped postcard.
Item D is Certificate of Delivery (sorry it is cut off)
Item D Business Reply to PCS probably nothing special here.
Item E Business Reply to Ronald Reagan. What would happen if I sent this today?
Item F Postcard of some sort?
Item G Marine Corps Recruiting Postcard
Item H Probably nothing here, but maybe the cancel?
Item I This cut off an envelope
Item J Has letter inside from USPS thanking Alice for sending a postage stamp idea.
Item K Business reply