I have been having trouble finding the answer to this question.
No. When you activate an ability, you must pay its cost. You can't activate two instances of an ability by paying the cost for one of them the same way you can't cast two spells for the same mana or activate one ability infinite times by paying its cost once.
If Lotleth Troll had a triggered ability that triggered upon you discarding a creature card, it would be different because now you aren't paying a cost.
no. it would read "discard a creature card: put a +1/+1 counter on each creature named Lotleth Troll" i believe.
Thank you both! That helps clear up a lot of confusion! :D