Yes there is a workaround and you are able to get mavericks on it but it is complicated, the EFI is 32Bit whereas any OS newer than 10.7 has a 64 Bit EFI. There is a way to modify the EFI on older Mac Pros so it is 64 Bit but its complicated.
Hey Patrick, the first light indicated that the Mac has power, the second indicated that there is power to the board, the thirds indicates that its communicating with the GPU and the fourth is that its communicating with the LCD. It is a possibility that when you installed the SSD that you may have unplugged either the power cable going from the power supply or the power cable going into the Main Board, check both of these.
http://www.ebay.com/itm/Macbook-Pro-15-Unibody-A1286-Mid-2012-High-Res-LCD-Display-Assembly-661-6506-/281770783950 This is the link for a new display and to repair it would take more time than replacing it and repairing it wont be a permanant fix as the adhesive will not be as strong as a replacement display.
The flashing question mark means it is unable to see the information on your hard drive for it to start up. If you have access to an external dock or USB to SATA, try taking the drive out and completely reinstalling the OS. If this does not work then its more than likely that either the hard drive or data cable to the board needs replacing. If you get stuck with this then use the hard drive replacement guide on fixit. Good Luck