All human life/lives

  1. All human life should be valued equally.
  2. All humen life should be valued equally.
  3. All human lives should be valued equally.
    Which is the right sentence?

The only difference between #1 and #2 is a spelling error.

In my opinion “lives” is more logical here.

Dozy,
“All human lives should be valued equally, be it Tamilian or Sinhali.”
Is this sentence OK?

You would need to use ‘be they…’ not ‘be it…’ but leaving that aside it is not a clear sentence. Are you saying those are the only two types of ‘human life’? That’s what it seems to indicate.

Beeesneees,
Can I write as below:
“All human life should be valued equally, be they Tamilian or Sinhali.”?

Are you saying those are the only two types of ‘human life’? That’s what your sentence indicates. It does not take account of any other race/culture.

Beeesneees,
“All human life should be valued equally, be they Tamilian or Sinhali or any nationality.”?
Does this sentence meet your condition?

It’s better than the original, though I really see no purpose in specifying the differences.
All human lives* should be valued equally, whatever the person’s nationality.

*Like Dozy, although both are possible, I prefer ‘lives’ here