No. Don't make it easier. Give players the ability to have 6bparty members OR put more roadblocks in the way so they level up to level 5 before the encounter. Use D&D 5e stats for Gith, that's fine, and remove height advantage and backstab and the encounter would be fine.
It's too hard because Gith can Mist Step to high ground and pummel you twice per round each while you are at level 3 or 4 and have like half their hit points. So they constantly have advantage and you usually don't unless you perch yourself super high before triggering the battle.
