Does it mater if i upgrade additional seats first or stadium, because of time to built?
Actually seats doesn't matter for other facilities - they will be built with the stadium upgrade (tho if you will upgrade seats, time will be reduced from stadium build)
What you need to do is upgrading the rest, such as score board, lights, grass and so on
Season 5 - Level 5
1st Season: League Winner, Cup Winner
2nd Season: League Winner , CL Winner
3rd Season: League Winner , CL Runner Up, Quarter Finals Cup
4th Season: League Winner, Quarter Finals Cup