audio for VOIP - filter and resample or viceversa?
Your order is fine. The biggest question I have is with,


Equalize, using a "voip" or "telephone" filter: discard anything over 3KHz and under 300Hz.


Since you are resampling to 8 kHz in step 4, you already have less than 4 kHz, I don't see the point in the 3 kHz limit. And knowing nothing about the 3 kHz filtering you're using, I wonder how much intelligibility you're losing in that step. This is easy enough for you to test.

I believe you'll get better quality but less dynamic range with ulaw, compared to alaw. Other than this, the compression (step 3) is probably the next most important aspect to experiment with.