I don't know much about Pikemen's Lament, but I don't think one would want to underestimate the rebels. They were well equipped with pikes and muskets that had been brought over by Monmouth, and I think a 2:1 shotte to pike ratio is likely. Although newly raised, they included a small core of experienced soldiers. The scythe men were intended as substitutes for grenadiers and might arguably be picked men - they led the infantry attack at Sedgemoor.
Also, it is worth noting that King James's battalions, although mostly professional soldiers, had been padded out with new recruits.