How many low level NPC adventurers to challenge a 12th level party?

[Quoz]

I'm planning on running a "Tucker's Kobolds" style scenario with a group of well trained and coordinated goblins defending their territory from my players. I plan on styling them as guerrilla fighters, complete with a charismatic over-the-top leader, complete with custom loot for the party to acquire:

Beret of Charismatic Leadership (Requires Attunement)
The user gains the benefits of the Inspiring Leader feat. If they already have that feat, they may increase the number of creatures they can effect each day to their level times their Charisma score.
Any creature with temporary hit points from this effect gains the following benefits: they may communicate telepathically with any other creature within one mile that also has these temporary hit points; and any beneficial spell or ability they use may effect twice the normal number of targets so long as all creatures targeted have temporary hit points from this ability and would otherwise be valid.

I want the "leader" to be a sorcerer or warlock of 7th level and the rest to be goblins and hobgoblins with 2-5 PC levels each. I want them to be tactical, using their ability to hide as a bonus action and fighting on home terrain in combination with spells like Pass Without Trace, Silence, and Fog Cloud.

So far I'm thinking 4 or 5 squads, about 1 per PC. Each squad will have 1 leader of 5th level and 5 2nd or 3rd level underlings:

Barbarian Lancers mounted on emus or some other exotic mount

Shadow monks and rogues

Fighters with heavy armor, shields, and spears fighting in a defensive phalanx

Archery Rangers

Support casters/healers

The terrain will be home field advantage: tunnels and other areas that allow normal move for small creatures but are difficult terrain for medium, pit traps that will only collapse for characters of a certain weight, and a number of trapped areas the players can be led into. This clan has had several minor skirmishes with the party so far and enough have escaped or survived that they know their capabilities and can plan for them.

So what do you think? Too mean? Not hard enough? Any special tricks they should throw in? These are supposed to be enemies vastly inferior in individual might but well prepared and highly motivated to defend their territory.

[Keravath]

My initial thought is that with 5:1 against each PC and a 7th level caster backing them up and all of them with temp hit points and able to coordinate their attacks across the entire battlefield so they can focus fire PCs at 20:1, 25:1 or 30:1 depending on the number of party members that they will take down one or more PCs/round. On top of that, they are all based on PC leveled classes and not the NPC type templates.

It may come down to how much AoE the PCs have available and how OP they might be in terms of gear. If everyone has +3 armor and weapons then it could be very different than if they have lower level gear.

Finally, how much crowd control does the party have? Wall of force, hypnotic pattern, web, plant growth .. depending on the fight location and which side gets initiative .. all of these could be game changers.

In a straight up fight with normal gear with a mostly martial party then the party might have some real trouble with so many opponents. Bounded accuracy lets lower level threats remain effective when used in numbers.

[Quoz]

Not a lot of AoE in the party. We have a Warforged Barbarian, Drow Necromancer Sorlock, Kenku Bard, Loxdon Paladin, Goblin Cleric, and half elf blaster warlock. I play our Conquest paladin but am rotated out to be GM. Gear is good but not epic.

To clarify I don't plan on engaging all at once, that would be too chaotic and way too much going on. Maybe two squads at a time, grabbing their wounded and retreating or doing hit and run attacks to sap the party resources.

For reference, last session before we leveled up we handled a Beholder Death Tyrant in its lair with minions while we only had 3 party members present.

[ZorroGames]

Oh, I thought this was mad villagers led by NPC adventurers swarm, prone, subdue, tie-up, and execute the “monsters” type PC scenario in the making. Like in the verity old monster movies or where the maddened villagers become shielded from magic by their righteous wrath.

Have to admit, I did not have a better suggestion than given so far yet, but will give it thought.