One option for your throwing spears that I'm particularly fond of is a simple slinger-tactic from classic Roman era warfare. Have these missile troops ahead of your line and launch a few rounds into the advancing enemy, then retreat behind your lines of combat troops, then split and send a group to each flank to harass spear-support and threaten the flanks while holding down your own.
The key to this maneuver is to space your advancing wall of CQC infantry apart to allow the "slingers" to pass between as they withdraw, and then close the heavier infantry together as they pass.

Hope that helps