Is levelling up an ability applied on previously used abilities?

To clarify, i will use four skills: Teemo's Noxious Trap (R), Shaco's Jack In The Box (W), Malzahar's Malefic Visions (E) and Kayle's Intervention(R).

If lvl 10 Teemo places a shroom with 200 base dmg, and then lvls up his R, will previously placed shroom have higher base dmg (lvl 11 - 325 dmg), or lower from the time when it was placed (lvl 10 - 200 dmg) ?

If Shaco places a lvl 3 Jack In The Box (W) with 1sec fear duration, and than lvls it up, will duration of the fear be the older one, or the new one (lvl 4 W - fear duration 1.25 sec)?

If Malzahar uses lvl 1 Malefic Visions (E) with 80 base dmg, and while it still lasts, upgrades it to lvl 2, will on the new tick damage increase to higher base value (lvl 2 - 115 dmg)?

If lvl 10 Kayle uses her ultimate (lvl 1 - 2 secs duration), and while it lasts upgrades it to lvl 2 (2.5 secs), will previously applied ultimate be 0.5 secs longer or will it last 2 secs?

I'm only asking about base damage and stats, not items impact and AP/AD ratios.