Sounds pretty normal to me, as Dan said a frame like that will amplify noise and what you describe sounds like standard noises that fixed bikes can make when slowing down without a brake.
My bikes usually make it, drenching the chain in oil can stop it but there's no point because it'll get dirty and wear out quicker, I found KMC 510 chains to be quieter than izumi but I just trust izumi more.
Sounds pretty normal to me, as Dan said a frame like that will amplify noise and what you describe sounds like standard noises that fixed bikes can make when slowing down without a brake.
My bikes usually make it, drenching the chain in oil can stop it but there's no point because it'll get dirty and wear out quicker, I found KMC 510 chains to be quieter than izumi but I just trust izumi more.