In short, a settlement between the parties can occur at any time. It is most likely to happen, IMO, after limited expedited discovery and before the ruling on a preliminary injunction.
If MNTA has utmost confidence in their patents, I don't see why they wouldn't wait until the ruling on a preliminary injunction. The potential to keep aL, and presumably potential competitors like tL down the road, off the market indefinitely is huge for MNTA. It would go a long way towards validating their competitive edge, not to mention keeping the very lucrative profit share with NVS on mL in place. (This is of course many times more lucrative than any kind of settlement would be for MNTA.) I would be surprised if MNTA is not seriously considering this.