Hello.

Could dengar (equipped with ig-88d crew and engine upgrade) make a free evade action, after a boost action if in the same list there is the ig-88c pilot?

Dengar does not have the evade action on his action bar, so I'm not sure.

Thanks!

Yes, ships may perform specific free actions if the ability to do so is granted to them by some other effect. In this case, Dengar is getting IG-88C's ability by using the IG-88D crew, so he can take the free evade action after boosting.

Thanks a lot!

A ship doesn't need to have the associated action icon in it's action bar to perform a free action that's specified in an ability's text. For example, Jake Farrell may perform a free boost or barrel roll after performing a focus action, yet an A-wing isn't able to perform a barrel roll normally. The ability text overrides this, and allows him to do it.