The most obvious sign, besides peace and love, of the person in the Illuminative State, is orthodoxy. If a person seems to be living the life of the virtues, but objects to any item held by Rome, that person is most likely not even through the Dark Night. Purgation allows for humility and prudence to shine forth in the soul.
One cannot be unorthodox and a saint. Some liberals think that saints can be anyone who is "good" and "happy", for example. Some iconographers make icons of those who were never orthodox and, even, outside the Church.
A great person in the eyes of the world who positively rejects Catholic teaching is not a saint. Even the depictions of such people show a confusion, as in this one below. I note, again, this Vatican document on the dangers of New Age religions and Eastern Religions.
http://www.vatican.va/roman_curia/pontifical_councils/interelg/documents/rc_pc_interelg_doc_20030203_new-age_en.html
This trap of believing that good people who seem to do good in the world may be saints causes confusion in the Church, and outside the Church.
No one is canonized without being straight down the wicket orthodox. In the wisdom of the Church, those canonized reveal obedience and dutiful humility towards Church teaching. No wiggle room for those cooperating with grace....
to be continued...