The full version of UUByte DMG Editor provides a suite of tools that are otherwise restricted in the trial version:
No. 7-Zip and PeaZip can extract but not modify. TransMac can write to DMG but has a clunky interface and costs $60. UuByte is the most user-friendly paid option.
If the user is using UUByte to create a macOS bootable drive, using a "cracked" version is highly inadvisable.