Do secondary weapons adjust their attack and agility like primarys due to range? For example, if I fire a blaster turret or proton torpedo at range 1, do I still get an extra attack die?

No, range modifiers are the special rule for primary weapons only.

Secondary weapons each have their own special rules as detailed on the card.

Also of note: Proton torpedoes are range 2-3 only, and can't be fired at range 1 (except by Major Rhymer)

A range 3 attack with a primary supplies one extra green die. It does not change agility.

Any upgrade card with the ATTACK header is a secondary weapon. They do not grant range bonuses to either the attacker or the defender, this includes cannons, turrets, illicit upgrades with the ATTACK header, torpedoes, and missiles.