Ben hops down onto the stairs behind the party and in front of the two twin soldiers marching down the stairwell from above.
Spectral vines spring out of three and reach for the leading soldier. The powerful little metal man tries to tear right through them. DC13 Strength check: 16

Meanwhile, Granny tries to shake off her stupor. DC 12 WIS saving throw: 10

Horatio grows twice his size, lifting the two boys, he tries to make a run for it through the pumpkin patch. But as he does, three fat pumpkins burst open, and a giant snake slithers out of each of them.  Giant snake initiative: 19 

"Hey!" yells one of the snakes. Another takes a bite at Horatio:
Snake Bite Attack vs Horatio: 22. Hit: 5 piercing damage, and Horatio must make a DC 11 Constitution saving throw, taking 15 poison damage on a failed save, or half as much damage on a successful one.

Meanwhile the tin soldiers batter Ben from behind with their metal fists:
Tin Soldier #1 Slam Attack #1 vs. Ben: 21. Hit: 4 bludgeoning damage.
Tin Soldier #1 Slam Attack #2 vs. Ben: 8. Hit: 3 bludgeoning damage.
Tin Soldier #2 Slam Attack #1 vs. Ben: 21. Hit: 4 bludgeoning damage.
Tin Soldier #2 Slam Attack #2 vs. Ben: 6. Hit: 8 bludgeoning damage.

Tiny, Ben, and Matilda may act next.

Ben:

Without the shield to protect him, Ben takes three hits and looks to be on the verge of toppling over himself.  Regretting that he gave the shield to the dwarf, Ben does his best to stand strong and shoo his friends ahead of him down and away.  “Keep moving!” he says through the pain.

If the others move down the steps and away, Ben will Disengage and follow as quickly as he can.  If for some reason they do not, he will stand his ground to protect them while using the Dodge action.

(can I still cast spells through Tiny while I'm a snail?)

(Titaani-Snail only has an Intelligence of 1, so she doesn't even know what a spell is. But you may direct Tiny to do anything that Tiny is able to normally do himself.)

(( Horatio Con Save = 5, 16 dmg noted ))

" Everyone keep moving.", Matilda yelled desperately.

Dash Action.

Disengage Bonus Action if the snakes attempt to engage.

(Y'know, that makes sense. I've yet to meet a snail smart enough to cast spells)

Tiny is going to continue to lead the kids away, taking the dash action. 

Dashing, Tiny leads the way through the pumpkin patch, but triggers an opportunity attack by one of the snakes as it passes.
Snake Bite Attack vs Tiny: 10. Hit: 8 piercing damage, and Tiny must make a DC 11 Constitution saving throw, taking 7 poison damage on a failed save, or half as much damage on a successful one.

Ben disengages from the tin soldiers and races down into the pumpkin patch, finding himself with a massive snake rearing up on either side of him. 

Matilda races past Gerrard, dodging the snakes entirely. 

One of the snakes goes after Horatio; one attacks Gerrard.
Snake Bite Attack #1 vs Horatio: 23. Hit: 7 piercing damage, and Horatio must make a DC 11 Constitution saving throw, taking 9 poison damage on a failed save, or half as much damage on a successful one.
Snake Bite Attack #2 vs Gerarrd: 7. Hit: 7 piercing damage, and Gerrard must make a DC 11 CON Save, taking 8 poison damage on a fail, or half that on a success.
The third snake just shouts again. "Hey! Halt! All of you! What do you think you're doing?" 

The tin soldiers close in from behind.

Ben and Matilda are up next!

Initiative:

x Titaani (snail version): 19
√ Giant Snakes: 19
? Chucklehead (location unknown): 17
   Ben: 11
   Matilda: 10
   Granny  (location unknown): 8
   Tiny: 8
   Horatio (giant-sized): 6
   Kids (held by giant Horatio): 5
   Tin Soldiers 4

Ben:

Looking at the snake who spoke, Ben says, "We are seeking freedom for those children enslaved here, as by the rule of Ownership they belong to themselves and with their families, not prisoners of the hag.  Now is your chance too!  Come to freedom with us!"

Persuasion if it applies:  11

Seeing the trap closing in around them, Ben says to Horatio, "Get them all to safety.  I'll hold the hag's soldiers here."  If Horatio seems to be about to pass out from the damage he has just taken, Ben uses his action to Lay on Hands on Horatio for 5 points of healing as he speaks to him.  If he is okay, Ben will instead Dodge and stand in the midst of the enemies, drawing their attacks so his companions may flee.

Tiny dissapears with a puff of purple smoke, sent back to the realms of Titania regardless of whether or not he made his saving throw. 

(Apologies - all references to "Gerrard" in post #2356, above, should read "Ben"...)

Matilda runs back to give the kids a chance to get away from the snakes.....she's becoming increasingly certain that she is about to lose either Ben or Horatio or both and is not happy.

She struck at the closest aggressive serpent, " Leave him alone!"

" Kids! Go!"

' Shortsword' Attack: 24 Damage: 12 + Sneak Attack 4

BA ' Small knife' Attack: 13 Damage: 2

(( Horatio Con Save = 13, 11 pts dmg noted = 9 HP left ))

Ben seems to make little persuasive headway with the snakes as he nimbly tries to dodge their jaws. Tiny vanishes.

With two swipes of her kitchen cutlery, Matilda, having turned around to face the snakes, cuts the head off of one of them. 

The five scarecrows staked in a line near the pumpkin patch begin to scream loudly.

Horatio is up next!

Horatio grunts through the pain (BA: Second Wind = +10 HP, new total 19), disengaging from the snakes completely to get the children clear (A: Disengage). Once he has gone as far as he can (30' movement) he realizes he needs to make it much further and pushes on (Action Surge - A: Full Movement = additional 30'). He yells back to the others, "We have to hurry before Chucklehead, Granny, or anyone else get catch up, hurry!" (FA: Talking)

( If the squares on the map are 10' each that should get him and the kids clear off screen. )

Horatio races for the distant treeline as the scarecrows continue to scream.

The two soldiers and the snake converge upon Ben (dodging) as the other snake springs upon Matilda.

Slam Attack vs. Ben: 7. Hit: 4 bludgeoning damage.
Slam Attack vs. Ben: 5. Hit: 4 bludgeoning damage.
Slam Attack vs. Ben: 7. Hit: 8 bludgeoning damage.
Slam Attack vs. Ben: 6. Hit: 6 bludgeoning damage.

Snake Bite Attack vs. Ben: 12. Hit: 5 piercing damage, and Ben must make a DC 11 Constitution saving throw, taking 6 poison damage on a failed save, or half as much damage on a successful one.

Snake Bite Attack vs Matilda: 24. Hit: 7 piercing damage, and Matilda must make a DC 11 CON save, taking 12 poison damage on a fail, or half on a success.

Ben and Matilda are up next!

Matilda springs back and runs like hell.

BA- Disengage.

30' Movement.

Action- Dash.

Ben:

Seeing Horatio get the children to safety, Ben smiles through the pain as he works hard, dodging snake bites and almost all the tin soldier attacks…almost.  The one that sneaks through his guard conks him on the side of the head, and the cumulative battering he has taken is too much for him.  Ben collapses to the ground, unconscious.

Death Save:  20