"any ideas who this informant was? scarpa sr?"

Dapps, it could have been Scarpa.
The informant does provide info on mostly Brooklyn based mobsters. I think all of them in the excerpt in my post were Brooklyn based. So we can assume the informant himself was based in Brooklyn. Also, most of them are connected or with the Colombos.
He talks about the Robilotto murder (a capo with the Gambinos) as well, which seems to suggest he had some inside info on that.
He also talks about Gambino´s crew in Baltimore and claim he was at the Patsy Corbi funeral with Carmine Lombardozzi and another Gambino guy. In addition he gives some info on how that crew got started. This seems to suggest the informant was a Gambino. But who knows?