I think he will eventually sign, but appearing to not be as easy as I initially thought as he has been pretty vocal about it taking a lot to get him there (I'm sure a lot of it is just posturing, but he seems like a really good kid, his grandmother definitely did a good job raising him).
In terms of there being a penalty for signing him for significantly over it very much depends on what kind of figure they had in mind for him. If they don't sign him they lose the bonus pool for his slot, so if they thought they could sign him right at slot or underslot they do not gain anything from not signing him. However, if they were negotiating with the thought that they would have to sign him to an overslot deal than they could use any money banked from the top 10 round on Wolfe without penalty, it would just have to count against their bonus pool for the top 10 round (anything over $125,000 after round 10 must count towards the bonus pool from the top 10).
http://www.lookoutlanding.com/2017/6/10/15776034/how-the-2017-draft-works-what-it-means-for-mariners
I think Jennings will end up eventually signing as well, but there are definitely scenarios where Wolfe could end up having a bit more money thrown at him.