He wrote and signed a letter to the newspaper with the other 6 Cuban students. The letter protested USA policy towards Cuban refugees. He didn’t want the USA to accept any Cuban pro-Baptista refugees. He wanted their blood. He wanted Castro to try them like “common criminals”. There’s no doubt that is Rafael Cruz.
I agree the Oswald one is not as clear cut, but it was four years later and there really weren’t that many pro-Castro Cubans in the States at the time. Both had lived in New Orleans in the 60’s. When he was at the University of Texas, there were only 15 Cubans altogether. 6 participated in the rally, including Cruz.
We don’t have a good timeline for Cruz like everything else about the man. I’m sure the FBI does though, since he was a foreign student participating in anti-American rallies.