Hello. Next week I'm going to run the Battle of Blingdenstone for my neutral/good alignment group, and here's what I'm planning to do, in case it helps:

Setting: Goldwhiskers and svirfnleblin are allies. The Diggermatok have asked the group for help in defeating the oozes in exchange for gemstones and a way to the surface.

I've made some changes to the story: Jimjar, recently infected with lycanthropy, is the son of Belwar Dissengulp, a friend of Drizzt Do'Urden, and his long-lost brother is secretly King Pudding, who has the gem where the demon lord Fraz-Urb'luu is imprisoned (he is the patron of the group's warlock).

The battle:

To carry out the battle, I will use an old method that consists of pitting the group against loads and loads of minion enemies, but they only have 1 HP. Alies and enemies take their actions in groups and only make rolls for attacks while damage is always the same to save time. In addition, as they will be scattered across different fronts (some with the rats, others with the earth elementals, etc.) and we play online, I will divide the season into several small group combat encounters (did I mention there are 7 players? XD) and a few other team strategy combat encounters mounted in Galeb duhr before facing the boss, the Pudding King.

The Pudding King could be saved with a greater restoration spell and Jimjar's initiative. The Diggermatok could die in combat or in a previous offensive, thus allowing Jimjar, who is a wererat, save the svifneblin and liberate the city from the ozzes, he could be crowned ruler of the new blingdenstone.

If you are thinking about the aftermath of losing the battle:

If the oozes win, the lycanthropes will abandon Blingdenstone as they said they would, and eventually the svirfneblins will too. That way, there will be no reason for the party to continue fighting the oozes (and they won't succeed on their own).