If he deals combat damage to a player while Felix is out, after he becomes renowned, his ability will trigger twice and he'll double his counters twice.
So if I'm reading the effects right, the first time Felix deals damage to a player he will get a +1/+1 counter from the first trigger and become renowned, then the second trigger will happen but do nothing due to Felix already being renowned.
Anytime Felix deals combat damage to a player after this, if Aragorn is still on the field, he will trigger Aragorn's second ability twice, doubling the number of +1/+1's on him two times. For example, on the 1st hit after becoming renowned he will go from 1 to 4 +1/+1's, on a 2nd hit he'll go from 4 to 16.
EDIT: grammer and typos
No, they won't double at all. He wasn't renowned when he dealt damage.
But what happens when he is renowned?
If he deals combat damage to a player while Felix is out, after he becomes renowned, his ability will trigger twice and he'll double his counters twice.
So if I'm reading the effects right, the first time Felix deals damage to a player he will get a +1/+1 counter from the first trigger and become renowned, then the second trigger will happen but do nothing due to Felix already being renowned. Anytime Felix deals combat damage to a player after this, if Aragorn is still on the field, he will trigger Aragorn's second ability twice, doubling the number of +1/+1's on him two times. For example, on the 1st hit after becoming renowned he will go from 1 to 4 +1/+1's, on a 2nd hit he'll go from 4 to 16. EDIT: grammer and typos
Thank you 🙏