The level is far too difficult to beat mowerless as you only get three Peppercopters and three Winter Aloes. Additionally, the early waves of magical cosplayers makes it even harder.

Also dead plants now deduct 50 points in this level, is this a glitch?

In the latest version the level only requires 9000 points and dead plants don't deduct or add points, are you sure you're playing on the latest version?

Yes I am

There’s no way that level in later versions deduct 50 points for dead plants. Discuss more about this in PvZ Travel Discord if you want.