The distinction between omnipresence & indwelling makes sense regarding creation's shadows & vestiges, where the former - not the latter - would apply.
For imagoes Dei, only distinctions per degrees of indwelling make any sense, e.g. growing in likeness, theosis, epectasy, holiness, intimacy, etc.
That's why Thomists, who properly dismiss a character - based beatific contingency, can't coherently introduce, instead, an indwelling - based contingency.
Impeccability, then, introduces an intractable universalist problem:
Whether with or without sufficient information, by definition, no one can freely & wholly reject God.
Impeccability is correct, of course.
Ergo, universalism is true.