For those who are awaiting NOI from Alberta, as you have noticed, they aren't giving NOI as frequent as they did between the middle to the end of last year.
My take on this is, they will only continue as they did last year once they get the number of nominations they can issue for 2020. This number is set by the federal government.
My advice, stay in the pool and ensure you still meet the criteria for nomination as per their website.
Your chances are high if your NOC is in high demand. While I'm not expert in AINP, I strongly believe that when they start issuing NOI as frequent as last year, your NOC while be more important than your connection to Alberta.
Alberta has their own criteria for issuing NOI which includes NOC, ties to Alberta (family, job, education). It’s not automatic that when you meet some of these criteria you will get NOI. They have their own internal criteria for sending NOIs. You just have to wait and see.
I just called them and confirmed that they do not need any ECA report for AOS application. Although, I have to submit sealed transcript from Alberta's educational institute.