# [Python 3], 214 <s>236</s> bytes

<!-- language-all: lang-python -->

    lambda n:[[[choice([s,[[c.lower(),'!'][c<'A']for c in s]][((i-n//2)%3+(j-n//2)%3<1)*(i*j>0)*(i<n)*(j<n)])," "][i==j==n//2]for j in range(n)]for i in range(n)]
    from random import*
    s=(("OIAE"*2+"SDLUNTRE")*2+"HVBMCYPWF?GNTR")*2+"ZXJQKGIA"

[Try it online!][TIO-j7jdojgd]

[Python 3]: https://docs.python.org/3/
[TIO-j7jdojgd]: https://tio.run/##VY9Jb4MwEIXP5Ve4lipsQrNKPURxI7KRfd8JB0qgMUpMZCNV/fXUpkmX7zDz5mnmSXP9TE4xq6QhOaRn7/J29ACrOo7jn2LqB8gRptT5c/wRcIRN/VF3Hb@mW7obxhz4gDIgXNdBiD6zQqGMnyo5FN1lrYQNRI3otah6jckayepiEwLoOpSQiBC1m4VFKox77D1Ackc59J@jhTy@qPEoG71cY54YmiAIwUnPakOjnIOL1nA1Xs7bEKupu26MmrvpplO3pfnt7bf92cDuWTD1hAh4AoSMCY5IYEJuEtbr7T9Yd3p3JjfGGfOMZcZQspCsJC2JbduNRrM5Gk2nnU63u15vNrvdoL@d7SHW1Ifs98OSWXoxy7iqPVw5ZQmQL/9IeGAwH8WUIXjrHAN1z9V9KFcxTr8A "Python 3 – Try It Online"

The multiplicity of each character is expressed as sum of powers of two, e.g `12 = 8 + 4 => "E"*12 = "E"*2*2*2 + "E"*2*2`.

`((i-n//2)%3+(j-n//2)%3<1)*(i*j>0)*(i<n)*(j<n)` may probably be golfed.