Okay well I figured out how to use TF2 Attributes but the only thing that works is the voice pitch attribute.
PHP Code:
TF2Attrib_SetByName(client, "player skin override", 1.0);
TF2Attrib_SetByName(client, "zombiezombiezombiezombie", 1.0);
TF2Attrib_SetByName(client, "SPELL: Halloween voice modulation", 1.0);