I can only speak for the Duratec engine which is 5W30 if semi synthetic or 5W40 fully synthetic.
As far as filters are concerned, simply look at what is fitted currently and there are plenty of conversion charts online for other makes. (I use Mann W7015 oil filter, but gdi could be different?)
Spark plugs should not need changing at all with so little mileage as they are not age related. However, it is important to remove them and re insert them annually to avoid them becoming seized in the alloy head. When removing, it is possible that you could find that one or more of the external bodies are rusted if the car has been out in the rain, in which case, you may choose to clean them up or replace with like for like.
Tips: once loosened, I like to stick a vacuum cleaner over the plug recess to suck out any debris before finally removing the plug. When replacing, only a light torque to about 14 lb-ft is necessary.
Greasing: lots of views on the type of grease. I use Millers Deltaplex 2EP, others go with Red ‘n Tacky, some like moly based products…at the end of the day, any grease at 500 -1000 mile intervals is better than no grease at all!
Good luck and enjoy.
