I think Debbie would wait. I expect Cain would just be under suspicion whilst the police make further enquiries and wait for results from forensics. I think Debble would be very scared that Pete could kill her if she made the wrong move and went to the police so soon. You know how many bad boys she's had close to her in life (Cain, Ross, Cameron,...) and seen a lot of bad stuff over the years, so she's experienced enough to know to just get Pete to stay away from her for now.
I think James would protect Pete over this, for a while anyway. He is his eldest son (usually the golden boy, as you wrote, mariba) and wouldn't want to lose another of his sons, at least not in such a short space of time anyway. If you remember, it was Pete who saved James' life when Emma made the loaded pallet fall onto James and nearly killed him in January 2015, so I suppose James still owes Pete a big favour for saving his life. James may just wait for the police to prove that Pete was involved with Ross' death (IF he is dead, only one of several possible theories for now, of course) as I expect the Barton family (what remains of it) will stay silent about Pete, even though they disown him and presumably don't have him living or working at the farm for at least the time being. It was an accident initially during an angry fight, but the final kicking by Pete went beyond accident maybe and there may have been a murderous intent behind this even if Pete hadn't meant for this when the fight began?