Do not confuse SATA with eSATA.
To your questions.
1) You can probably get video files from the external Drive but it is not sure. How will the external drive be formatted ? If it is a standard Win or Mac Format you wiull be able to acces the Files (Acces means you will see them, than the question will be again as in my previous posts which video-file kind are they ?
Some TV (like Samsung) let you connect an external HD for recording but the HD has to be formatted by the TV and it is done in a way that you cannot read it with PC or MAC or even with a different Samsung TV. In some way the TV Code is enbedded in the Formatting. Others like the German Clarketech let you record on any HD or even USB key or card and you can convert the files as you like.
You need to go on reading the user guide or experiment.
2) I do not believe you can "download" the data from the SATA (or eSATA) port of the TV to a caomputer.
Than there is also a legal question. Each contry has different rules. In Italy we can copy TV sendings and even make a personal copy for backup of a movie but frequently the movie are protected and you cannot do it.
And you are going to copy movies...