1.Stats: Should Purugly get a stat boost, Evolution, Mega Evolution or nothing?
Purugly's stats are atrocious, especially due to its late level. It is 27 BST weaker than its counterpart Skuntank. With this in mind, Purugly can have about +30 BST update, which will give 172 BST gap. from Glameow.
An evolution would be closer to Magnezone and Mamoswine, much more defensive or powerful. It is unlikely, however, as the only cat Pokémon with three stages is Incineroar.
A Mega Evolution would not be too beneficial. It is statistically too weak to make it work, and its typing and abilities, alongside its moves are pretty bad.
2.Should Purugly get more abilities?
Purugly already has three abilities, but potential abilities would be Prankster, Fur Coat, Technician, Speed Boost, Tough Claws, Super Luck and Intimidate.
Quick Feet, Strong Jaw and Limber would also work.
3. Should Purugly get more moves?
Yes. Purugly has a very limited movepool compared to its counterparts. Some potential moves would include:
-Wild Charge, as it gets Thunderbolt.
-Earthquake or Stomping Tantrum, as it gets Bulldoze.
-X-Scissor, Psycho Cut and Swords Dance, due to its claws.
-Tail Slap, due to its odd tail.
-Bounce, again, due to its odd tail.
-Superpower, as it gets Wake-Up Slap.
-Double-Edge, for having a strong STAB move.
-Crunch and Elemental Fangs, as it gets Bite. Psychic Fangs in particular would work.
Nasty Plot for sake of flavour would also work. So would Agility. And Baby-Doll Eyes for Glameow.
4.What additional typing Purugly can have?
Dark is the most obvious choice. Fairy is a lesser choice. Ground and Electric can also work.