Firstly welcome to Heresy,
Second, you can't mix units, you could however have 2 seperate units helping each other, for example, 10 Howling Banshees charging a unit, with 10 Dire Avengers providing cover fire.
As you seem to know already the different Aspects have different strengths and weaknesses, so if you want to run multiple Aspects, its wise to choose Aspects which complement each others abilities.
Definately try out different combinations of Aspect warriors to see which ones fit your playstyle.
Grish.
Second, you can't mix units, you could however have 2 seperate units helping each other, for example, 10 Howling Banshees charging a unit, with 10 Dire Avengers providing cover fire.
As you seem to know already the different Aspects have different strengths and weaknesses, so if you want to run multiple Aspects, its wise to choose Aspects which complement each others abilities.
Definately try out different combinations of Aspect warriors to see which ones fit your playstyle.
Grish.