Question 1: How long does I-526 take?
This question has a nice answer for new petitioners: much less time than before.
As inventory falls and flow rate increases, processing times fall. People who filed I-526 in 2016/2017 entered at the top of a mountain of pending petitions (as illustrated in Figure 1), and have suffered long processing times as a result. But people who file I-526 now in November 2018 are just standing on a molehill by comparison, plus benefiting from improved completion rates.