Wandless magic isn't a special feature; so much as something that older, more experienced wizards are able to do in a limited way in certain circumstances. I'm sure you've already read through the
wandless magic guidelines; while it does mention special features, this really does mean things like elementals (who aren't capable of doing conventional magic once fully trained anyway) and very special cases where there is some kind of special innate ability.
I'm a bit confused as to which SF you want for Seva, now. You've already talked about animagus and metamorphmagus, and now you're looking into wandless healing... we don't ever approve more than one SF per character, and tbh we're less likely to approve one person's original feature for someone else unless the creator has given their approval, so that's something else to bear in mind.
Hope that helps a bit!