I can create a default “Hello World!” application through File > New > MicroEJ Standalone Application Project which builds and simulates as expected.
If I remove the bin folder (and others that were generated bnot in the default project) and perform a rebuild, the SOAR process fails as the Main.class file is not regenerated. Touching the main.java file can force it to be rebuilt, but this is undesirable. Is there a step I am missing to regenerate application dependencies?
Yes 
Window > Preferences > Java > Compiler > Building > Output Folder > Rebuild class files modified by others… of course.
Also, is there a way to remove/correct the EasyAnt Console error seen below, when using a project source platform?
BUILD FAILED
Found an error when building test
* Where
File : C:\Program Files\MicroEJ\MicroEJ-SDK-19.05\rcp\configuration\org.eclipse.osgi\464\data\repositories\microej-build-repository\com\is2t\easyant\plugins\platform-loader\1.2.2\platform-loader-1.2.2.ant
Line : 165 column : 55
* Problem Report:
No loaded Platform.
Possible options to load a platform are:
[snip]
Cheers,
Dave