Good news is that a year in consulting isn't long enough to look like a detriment. Bad news is that the job market is crap right now.
Is anyone aware of any firms that do formal-methods-like activities
Don't limit yourself to what you studied in your PhD. A big chunk of the commercial research position will be focused on AI.
Has anyone got experience making a shift from a non-technical to a technical role?
Don't think of it as a shift from non-technical to technical role. Think of it as "I finished my CS PhD about a year ago and now I'm looking for a research/software job".