The Metamask spamming campaign primarily use their own list -- compromised credentials are mainly used to get SMTP access and then spam away until they get caught.
I can corroborate the same, no spam
As of now I haven't yet received spam/phishing from this breach either
me too - I haven't received anything from namecheap despite being a customer for 10 years or so
FWIW, I also have some namecheap domains and I didn't get anything