1) I recommend using the prefix mcb_ (short for multiple content blocks), so the function names will be mcb_the_block(), mcb_has_block(), mcb_get_the_block(). The plugin already defines other functions with the same name so this prefix is logical.
2) I recommend changing your theme code that uses has_block() / the_block() using function_exists(). That way, the site wont display fatal errors / display a white screen.
