Thank you for your inquiry. In researching the fate of STANVAC CALCUTTA, I see that the Armed Guard website indeed notes three deaths among its Armed Guard crew (per http://www.armed-guard.com/panama.html#calc). This may be in error.
The website American Merchant Marine at War (http://www.usmm.org/), which you consulted to learn the names of the six wounded Armed Guard crewmen, has a different summary of the fate of the Armed Guard crew. Although a little difficult to decipher, http://www.usmm.org/sunkaz.html#anchor29645 shows that there were 14 deaths among the merchant crew; 26 merchant crewmen and nine Armed Guard crewmen (i.e., all of the Armed Guard crew) were interned in Japanese POW camps; and one merchant sailor ended up in a German POW camp.
This outcome is described, in great detail, on another web page, http://www.usmm.org/calcutta.html.
In short, there were no deaths among the nine Armed Guard crew. Rather the entire Armed Guard crew was interned in Japanese POW camps for the duration of the war. All the men survived their internments and were released at the end of the war. I take the information found at usmm.org likely to be more accurate than that found on the Armed Guard website.
There is additional information about one Armed Guard sailor's experiences both on the ship and while in the POW camp at https://www.armed-guard.com/lvc.html; scroll down the page about half way.
Ron Carlson, Webmaster
Armed Guard / Merchant Marine website