First Build: Discussion and request for comments

Hi there,
So, I wanna build a FreeNAS box. This thread is me thinking loudly/foolishly. Its kinda of public brainstorming, so please bear with me and help if you think you can.

Objective:

1. MediaServer (Plex)-> clients two Roku's connected to Plasma TVs + 1 LED Smart TV. Max 2 concurrent streams.
2. Backup phone data (mainly pictures/videos).
3. Backup 4 laptops 1 PC
4. Backup 3 tablets/iPads.
5. Archive 20 years of old video tapes (around 50 to 60 8mm and Hi8)....

First Build: Discussion and request for comments