Oil on spark plugs, engine missing out

I am new here and would appreciate any opinions on this.
1) Have oil leak under car, gatage thouhgt oil pan seal.
2) Dash cluster completely went down one day last week...nothing works except for little bulb showing I have a light out.
3) Next day car began running very rough.
4)garage ran OBD and engine computer scan thought I needed a new dash instrument cluster and also coil pack 4 #4 cylinder.

I ordered a coil pack and thought before I got it I would cahng plugs. In pulling out 1-4 they came out covered in oil and you could not even see the threads. 5-6 towards passenger compartment were dry. After changing the plugs still ran very rough so i will install new coil pack for #4. I am basically in a world of hurt with all these problems and would really appreciate any thoughts and suggestions. One thing on the dash cluster i thought of was that i had a power inverter plugged in for my computer and on a sudden stop water got in it from a bottle. Did not do anything then but 2 days later the dash issue surfaced, by the way cig lighter not working also. Didn't know if this may have done something to electrical/dash. Again any help appreciated!