I think you can (depending on how the powdered milk was made), but the flavour may suffer. You'll want to use skim milk powder and mix it with an appropriate amount of cream ("half and half", or 18% "light cream" is apparently fine). Of course you also need calcium chloride and rennet, but I guess you'll be able to mail order it. Guam is pretty small. Are there *any* goats on the island? It might be worth looking around to see if you can find anyone raising them. I imagine cows are right out :-) (similar to Okinawa). This PDF from the University of Guam seems to imply that *maybe* there are some people raising goats? If you could find somebody, maybe they would be interested in a milk for cheese swap :-)