I have the same concerns and I have been emailing schools asking for clear explanations.
For your first question,it depends on the school/department,Some schools need both while others are satisfied by uploading your transcripts unitll you are accepted then you must send your official transcripts.
For your 2nd question, 2 schools said it explicitly,send us unofficial / photocopies of your transcripts and if you got admitted,then you MUST send us the original official hard copies.
Actually,every school has its own rules,email them and see.