I'm a little confused about which date should go on our timeline. I haven't actually received my NOA1 yet, but my check was cashed and looking at the electronic image online I was able to make out the EAC number. Should I use the received date that is shown online for the case status as my NOA1 date? Or should I wait until I get the NOA and use the notice date?

I used the receipt date that was on the actual NOA. As example, the receipt date was February 23th and the notice date was the 25th I used the 23rd for my timeline.