Yes, but you have to be level 12 to do this

The Sage Advice articles says:

You can also use Pact of the Blade to bond with a magic weapon, turning it into your pact weapon. This magic weapon doesn’t have to be a melee weapon, so you could use the feature on a +1 longbow, for instance

This takes care of the ranged pact weapon, and allows the use of both Thirsting Blade and Lifedrinker with a ranged weapon. This means you can attack twice with your Attack action using a magic ranged weapon.

And the Sage Advice compendium says:

Does Crossbow Expert let you fire a hand crossbow and then fire it again as a bonus action? It does! Take a look at the feat’s third benefit. It says you can attack with a hand crossbow as a bonus action when you use the Attack action to attack with a one-handed weapon. A hand crossbow is a one-handed weapon, so it can, indeed, be used for both attacks, assuming you have a hand free to load the hand crossbow between the two attacks.

This allows you to attack twice -- once with your action, another with your bonus action. Since you have Thirsting Blade (which works with any weapon as long as it's your pact weapon), you can get three attacks in all.

However, while Thirsting Blade is available at 5th level, Lifedrinker is available at 12th level. So to complete this build, you have to be a 12th level character at minimum. Most of it, you can enjoy from 5th level onwards though, as only Lifedrinker is the high level component.

The bonus only applies to weapon attacks.

The text of Improved Pact Weapon states (emphasis mine):

In addition, the weapon gains a +1 bonus to its attack and damage rolls.

Spell attacks and damage aren't attacks made with the weapon, even if it's used as a spellcasting focus for the spell. Further, a spellcasting focus is only used for spells which require material components.