One of the best ways to understand how things are affected by ui selections is to try them out, and then check the generated code to see the difference. - pass through will generate explicit SQL pass through code The other two I haven't used but they most probably will let you tailor the most appropriate/efficient approach for remote data in your specific situation.
Need to connect to databases in SAS Viya? SAS’ David Ghan shows you two methods – via SAS/ACCESS LIBNAME and SAS Data Connector SASLIBS – in this video.