Is it possible to save my alt to Ulduar with only Yogg-Saron alive, then having my friend enter the lockout, leaving the instance on my alt and joining the run on my main? Could I save this reset if I extend it on my alt every week, then kill Yogg-Saron on my main? The main issue I have with farming this mount is having to clear the whole instance every week, it would be much easier if I could just grab my alt's reset every week.
The same goes for ICC25, could I just have my alt give me a 11/12 hc reset every week?