First, welcome to Elite Dangerous.If you get pulled out of supercruise when you're a beginner, they're normally pretty kind to you. They're always similar rank to you and the low rank ones don't even seem to know which way to point. They won't be like that forever, so it's worth practicing what to do when they hook you out. When carrying cargo or doing any missions other than combat ones, always fly with 4 pips to engines and 2 to shields. The moment they drop you into normal space, boost, boost again as soon as you can, then engage your FSD as soon as it cools down. I've never needed chaff or any other countermeasure other than speed. For that to be 100% successful, I always use A-rated thrusters and power distributor and save weight where I can to make my ship the fastest possible.
While boosting away, roll your ship.
FA Off will let you start the roll and forget about it, but can be done easily with FA On.
The point is to not let your ship, especially the thrusters, be a steady, non-moving target.
As the enemies become better (your combat rank determines their combat rank while your ship determine's the interdictor's ship), they'll know which way to point.
You could also research interdiction avoidance tactics if you find them difficult to win or don't want to be bothered with the mini-game, although avoiding them is a mini-game too I suppose.
The Nav panel filter's default is to show everything. You must have changed it at some point. The X next to the Filters button on the panel will clear whatever is set and everything will be listed.
The type of missions offered by each system minor faction (MF) are generally determined based on the MF's State. MFs in Boom state should offer you courier missions more often than other states. Sometimes they persist shortly after the state changes too.
It will usually take multiple mined fragments to make an entire unit/tonne/ton of the substance. After you've got the detailed scan of astro-objects in a system, the system map will tell you what type of reserves the system has (ie, Pristine, Common, Low, Depleted, etc). Check the 2nd tab on the left side of the SysMap. Reserves applies to the entire system while rings are made up of different types of substances, such as icy, rocky, metal rich, metallic, etc) and is listed just after the description of the type of body but before its statistics.