A creature that’s a Wolf or Werewolf enters the battlefield with one +1/+1 counter if it would otherwise enter with no +1/+1 counters.

A creature that’s both a Wolf and a Werewolf receives only one additional +1/+1 counter from Arlinn’s ability.

If Arlinn leaves the battlefield before her last ability resolves, most likely because she only had 2 loyalty when you activated the ability, the Wolf token won’t enter the battlefield with a +1/+1 counter.