The diamonds signify that the plug-in chip has a significantly lower memory usage cost to equip compared to abnormal version of the same chip. I've had chips with diamonds cost 10-15 less memory to use before, so they're definitely worth looking out for.
If you combine chips with a diamond next to it, make sure you combine it with another with a diamond, to keep the cost down. If you combine it with a regular version of the chip, it may slightly lower the cost from what it would usually be, but it will lose the diamond status and cost more than it would if it had the diamond, unless the regular chip has the minimum cost without the diamond, as explained here:
To explain further, an initial level diamond ◆ chip, or level 0, will have a cost of 4 and the basic equivalent will have a cost of 5-10, however the 5 cost can be fused with the diamond chip to get a diamond ◆ chip +1. The basic chip to retain diamond ◆ rating will always cost 1 more then the diamond ◆ version.
The same however is not true for even upgrade ranks (Ex. +2, +4, +6,) as the formula for fusing chips will cause an extra increase and instead of gaining a diamond ◆ of the next rank will give a minimum basic. (Possibly useful if you have the chips you'd need for higher ranks but not enough of lower ranks.)
Note that, as mentioned in the article, this only works on odd numbered upgrades.
Taunting was not a mechanic that was explained in depth at any point, at least not until you start Route C/D and start controlling A2. Taunting as A2 is pretty straightforward, but apparently all characters can taunt.
According to the wiki, anyone can taunt by repeatedly flashing your flashlight in enemies' faces. The flashlight can be toggled on PS4 by pressing the L3 button and 2 on PC.
All characters can taunt by toggling the flashlight repeatedly with the enemy in the light's path.
Additionally, A2 can taunt enemies by holding down the light attack button (this is in lieu of an additional attack that 2B and 9S have). When A2 taunts this way, it affects a larger area than toggling the flashlight.
Best Answer
Unfortunately, you don't. You don't meet the requirements to install physical media.
Sometimes, games come with a, "redeem code" that you can use to register the game in Steam, Origin, or the like. That allows you to install the game digitally. If the physical disk doesn't come with that, then I'm afraid you're out of luck. Your only options are: