Are the rioters being charged with breaking federal laws? And if so, could Trump issue pardons for them?
FBI is working on this. So I'd expect federal charges.
Technically yes, Trump can pardon them. But I think he is inherently selfish and would likely understand doing so would turn things further against him. So I don't expect he will.
What happened on Wednesday was way bigger than the fate of a few (or a few thousand) people. It broke the tradition of 200+ years of peaceful transfer of power. To me, it appears to have broken, or at least eroded one of the foundational ideas that define the US.
Despite what may appear superficially, some Republicans/Conservatives do still have a sense of civic pride and do understand the gravity of the incident. Trumpers, mostly, don't! However, even if Trump is unable to understand exactly what he did, I suspect he does understand the depth of the backlash and would likely not further inflame passions. My reading is that he has a pretty strong self-preservation instinct.
But then, I have been wrong before!