Larian Studios Forums Baldur's Gate III Baldur's Gate III - General Pact of Blade confirmed via interview

No. Those were never invocations.

Lifedrinker
Source: Player's Handbook
Prerequisite: 12th level, Pact of the Blade feature

When you hit a creature with your pact weapon, the creature takes extra necrotic damage equal to your Charisma modifier (minimum 1).

Thirsting Blade
Source: Player's Handbook
Prerequisite: 5th level, Pact of the Blade feature

You can attack with your pact weapon twice, instead of once, whenever you take the Attack action on your turn.