FTE give you nothing other than a wage. Spain has a health system which as an EU national you can use. You can then top up with private health care. You will see two those of hospital in Spain the NHS type and the Medicare type.
Yes the Spanish will tax you on world wide assets regardless if your domicile for the UK and its at the Spanish higher rate.
If you gave a family that you want to up and move its a very big risk if your contract does not pan out.