You can remove all of that to satisfy `vrms`, if that's all it complains about.  However, the real RMS would, I am certain, inform you that there is no way to make the pi truly free, since it requires some proprietary firmware in order to boot.  I mention this because it is always possible that in the future the virtual will become more real, in which case you will encounter some insurmountable obstacles.  Right now `vrms` presumably does not check for such things (they could likely be easily concealed anyway since they are loaded before the kernel).

> 1. Regarding all these firmware-* packages

Those having nothing to do with the firmware mentioned in the last paragraph.  They're binary blobby things that *can* get included with the linux kernel due to the difference between Linux Torvald's and Richard Stallman's attitudes toward open source licencing, but I believe they aren't in the vanilla tree because they are not open source. They aren't used by any of the pi's own hardware. If you have peripherals that need them, you would either know, or easily recognize that you did once you remove them.  You can put all this stuff back as easily as you removed it anyway.

**The ethernet chip is not made by Realtek,** or Broadcom, it's by SMSC (recently absorbed by Microchip Technology).  Not all firmware is closed source; also, it may be installed by the manufacturer.  I don't know which is the case here, but if I had to guess it's the latter.  I.e., that firmware isn't from the kernel, and it isn't from a Raspbian package.

You can see what files were installed by a package with `dpkg -L`.  Those all populate `/lib/firmware`, which is where a kernel build places stuff that's in-tree.  Hence there's a lot more stuff than from those non-free packages, since the default Raspbian kernel includes it.  But there's no SMSC firmware there.

I've completely removed `/lib/firmware` on a B running Raspbian jessie, and it boots up and connects to ethernet.  Again, none of the `/lib/firmware` stuff has to do with the pi's own hardware.

> 2. What would I lose exactly with removing pistore

I've never used pi store, but not because I have anything against it; I use google play on Android, etc.  There are [surprisingly few references][1] to it here.  Once again, certainly nothing crucial.

> 3. Is there anything vital that ships on the standard Raspbian that depends on oracle-java8-jdk? Or on wolfram-engine?

Regular Debian doesn't include any java, but if you want a FOSS version one is available ("iced tea", aka. openjdk); I'm not sure that it's up to version 8. **The system doesn't use java for anything anyway.**

Wolfram-engine was added by default to Raspbian (it's not in normal Debian) for the Pi Foundation's own mysterious reasons.  If you don't need it, you can remove it.


  [1]: http://raspberrypi.stackexchange.com/search?q=%22pi%20store%22