Another vote for the Larue MBT trigger. I have two and they're both great. I'll pick up another for my next build as well.
BCM has the A5 buffer tubes available(no VLTOR/A5 kits if that's your flavor), but you can assemble your own with the A5 buffer tube, a rifle spring(or a springco rifle spring), and an H0, H2, or H3 buffer.
CMMG (minus trigger) parts kits are available on primary arms for $30 for their 4th of July sale.
For grips, I personally like the magpul K grips because I shoot squared with "C"/beer can grip, but the MIAD grips are good too. Heard great things about the BCM gunfighter grips, but I have no experience with them.