Checking the rules is of course the best recourse, from 15.28:
Neutrality Discussions: Place a friendly Influence marker in one Neutral Country, or remove a Neutrality or enemy Influence marker from one Neutral Country.
Seems pretty straightforward that the answer is no. The rule allows placing an influence marker, not activating a minor as an ally. Check the wording of 15.19 for an instance where you can activate a minor ally.