Unstable Mutation gives a creature +3/+3 and then each upkeep -1/-1 in the form of counters.
Question #1 - Does the +3/+3 effect of playing Unstable Mutation count as 3x +1/+1 counters?, and if so can playing it trigger the sac trigger for Ordeal of Thassa ?

Question #2 - If I have both Unstable Mutation & Ordeal of Thassa on a creature and each upkeep i'm putting a -1/-1, and a +1/+1 during my attack phase do they simply cancel out or are there two sets of counters on the same card simultaneously? (the creature wouldn't eventually die from the -1/-1's because during the attack the +1/+1 negates the upkeep cost, is this correct?) It seems like I wouldn't be able to get 3x +1/+1's to be able to sac Ordeal of Thassa to draw cards if the counters are canceling themselves out.

Any clarification would be much appreciated!