The strata manager can’t re-appoint themselves. However it is commonplace for strata managers to ask for a re-appointment and be granted it on the grounds that the strata scheme isn’t ready to run its own affairs.
Be warned that your weight of evidence might be more likely to confirm the reappointment than persuade the tribunal otherwise – unless you can prove that the strata manager hasn’t done their job properly.
And, to answer your question, no you don’t need to provide your evidence in advance as there is no longer a paper assessment of a case before a hearing.