From the COBOL Language Reference
manual, section 220.127.116.11 on the VALUE clause:
The VALUE clause must not be specified for a data description entry that contains or is subordinate to an entry that contains either an EXTERNAL or a REDEFINES clause. This rule does not apply to condition-name entries.
so you will get a syntax error if you attempt this.
The mere fact that you can ask such a question indicates you have no
understanding at all of REDEFINES. In your example, WS-VARK and WS-VARN are not separate variables -- they are a single area of memory that has two names. If you move something to WS-VARK, you have changed the value of WS-VARN. If you move something to WS-VARN, you have changed the value of WS-VARK (or, at least, the first five bytes of WS-VARK). There is no distinction between the two. If you display them, you will find WS-VARN has the same value as the first five bytes of WS-VARK.
And before you ask, a PIC 9(05) variable that is USAGE DISPLAY will display alphabetic characters just fine. If you attempt to do arithmetic with the field, you will find the value is 12345 due to the internal representation of USAGE DISPLAY numeric variables and alphanumeric variables.