Your tap nitrates are unusually high (mine are 0-5 ppm right now, and were 10-15 ppm when I lived in UK), and we don't know how much trace minerals your water contains..
Have you decided on your stocking yet? If you get the same results from day 86 to day 90 as you got on 84 and 85, I think it would be safe to consider your filter cycled.. but *only* if the results are consistent! Because you're still getting some ammonia and nitrite, you will not be able to stock as fully as normally after a fish-less, but at least half-stock with plants should not be a problem.
Also, what's the water volume and the filter you're working with? What media do you have in your filter?