[Availability update | July 28th, 2020 | Microsoft Lists began roll out to Targeted Release (TR) customers in Microsoft 365, planned TR completion by end of August 2020 where we'll then begin broader...
Hi PamDV - glad you like it. A few answers to your questions:
Lists lightweight rules are not based on Power Automate - they exist on the list and can be defined by the list schema (columns) and changes to the list/list items. And for more complex workflow, Lists integrate with Power Automate flows to push and pull data in and out of additional sources with more complex serial or state-based actions.
Yes, you can attach files to list items, and if your scenario is more document specific, you might consider starting with a document library - that contains same list capabilities for columns, rows, views, etc. (built on same SharePoint platform).
Yes, you can customize both view and edit forms - either simple configurations within the list forms or more highly customized by using the Power Apps integration.
Per list migration, first know that a list is a list is a list. SharePoint lists will get all the new innovation - there is only one list product with several new entry points very shortly. So, some migration scenarios may simply be kept put knowing the update is coming. And per list migration from one site to another - today you could export to Excel and re-import the data from Excel into the desired site, or for more complex needs - see this answer in answers.microsoft.com.
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