Simple answer: YES Everything can be fixed. You can either replace the whole screen and digitizer which will be more expensive but easier to do, or you can replace just the glass which is a lot cheaper but will be a lot harder to do (you'll be swearing until the swear jar is full)
Sounds like the LCD is done for. However try turning power off for a few hours while on charge and then turn power back on if screen still the same get a new LCD as swap it out
The blue light slowly dimming will be the capacitors and is nothing to worry. I've had this problem before and was rectified with software upgrade found on the menu screen
The display for the original Apple Watch and the series 1 can be interchanged as the only thing changed really was the processor speed. Ive also just doubled checked on here and both have the same screen/digitizer, Item Code: IF308-009 Hope this helps