You could paint the caulk the same colour as the wood using either a standard emusion paing or artists acrylics paints mixed to suit.
Most DIY shops or builders provideres should be able to supply cream screw caps, and also most of these who sell worktops will also have a range of fillers colour matched to the tops for chip filling.
Yes, you can get upward opening hinges for kitchen cabinets. These are generally spring loaded to hold the door open when required. the Panelling Centre or other providers should be able to supply these.
Leo