Since the evolution is version exclusive, I have Pokemon Scarlet with a small Charcadet, which evolves into Armorouge with the Aususpicious armor. So is it possible to evolve my little Charcadet with the Malicious Armour while in Pokemon Scarlet if the Malicious Armour is transfered into Scarlet?
Yes--You can manually evolve a Charcadet with the Malicious Armor in Pokemon Scarlet. You'll need to trade with someone that has Violet (By having the person that has Violet trade you a Pokemon holding the Malicious Armor). From there you can use it on your Charcadet and it will evolve into Ceruledge.
(I tested this beforehand)