IIRC LMoP came with a high elf evoker wizard, lightfoot halfling thief and hill dwarf life cleric as well. Can we compare these to those and see if there are any mechanical differences?
There aren't. The spell selection is different, there are some equipment differences, and the new pre-gens lack Ideal, Bonds, and Flaws. But you could make these characters using the SRD from 2014.