The Asians workers on the Burmese end of the Railway were all native Burmese and hilltribesmen. There is no indication that any other groups (Javanese or Thai) were ever imported to work there.
The most oft quoted number for romusha is 270,000 but this is thought to have originated from the Thai-side only. It is estimated that as many as 200,000 Burmese nationals were impressed into service. It is, however, suggested that desertion rates were so high that at any given time there were less that 100,000 actually working the Railway.
As for the Allied POWs in the Burma Sector, they were primarily Dutch and Australians captured in the Dutch East Indies. There were only a few hundred British and Americans. The vast majority of the US POWs spent their time on the TBR in the Burma Sector.
Overall, the death toll in Burma closely paralleled that in Thailand averaging about 20-24% for the POWs and 40% for the AFL. It should also be noted that the cholera outbreak that killed hundreds of POWs and thousands of AFL in the spring of 1943 had a much lesser impact in Burma.
Unlike the workers on the Thai Sector, the Burmese were never consolidated after the TBR was completed. For the most part it is thought they simply melted back into the jungles and found their way home.
The authors of this website have no knowledge of any survivor accounts by any of these men.