Everyone hello and humble greetings on this fine day.
Enlightenment is one of those words as Greg Steckel points out that is open to a broad interpretation. If I may offer a few cents. The definition of enlightenment in terms of Aikido can be very broad and obscure for those who bring in loosely associated similarities to the Founder's experience creating a myriad of definitions. It is possible to come to define enlightenment via Aikido, the Founder clearly stated it.
Let's began with saying Aikido isn't religion. To some it maybe observed as a religion, but acutely it is a budo. There are others who treat it as a personal spiritual path of development. Spiritual to them is more than the simile of personal growth and development. Aikido becomes substitute for conventional religion. But again, it is a budo. The Founder did have spiritual beliefs instead of a conventional religion like that of mono-theism.
The Founder and his belief system a mix of budo and Omoto-kyu is more of a movement then a conventional religion. In comparison, there is more similarities with the Judo Shinshu Budhism than any of the mono-theistic religions. Spiritual beliefs and laws that much of the world has been influenced by and practices. Much of what the Founder propagated wasn't salvation, but social reform. The Founder's enlightenment was the importance in the preservation of peace, the ending of people hating each other to the extent of wanting to kill others, the elements that create war. That was enlightenment for him.
Going by the Founder's definition of enlightenment is a realization of social and personal reform. The Founder grew up under the last glimmering light of the glory of the Samurai. Times were killing and war was the only way of life, it was glorified and romanticized. Peace and preservation of life wasn't highly valued, spilling of blood, death and war was, in the times of the Samurai. The Founder's enlightenment wasn't spiritual as it was social reform. An enlightenment is more along the lines of an Age of Enlightenment Japanese style. A personal transition of the way to live and see the world leading to social reform.
The definition of enlightenment is less obscure than what it is made out to be. It is a realization that peace is more important than war. Love (not the best choice of word imo, better is compassion) over violence. A similar message Christ and others taught. A message that has gone unheeded in many parts of the world who insist war; senseless slaughter of people is the way. The realization of peace over war/violence especially and initially for Japan. The Founder clearly defined enlightenment for Aikido.
Footnote: If I am not mistaken the word "dojo" as well as the physical place has its contextual root in Jodo Shinshu. The dojo is a spiritual place but is is defined and observed by that of Jodo Shinshu Buddhism. Yet, many dojos traditionally incorporate Shinto elements such as the kamidana/god shelf the mantle of the dojo. The dojo has a dual spiritual elements and meaning in practice. Aikido Kamadanas are not generally the typical Shinto Kamadanas you see in budo dojo's, but the Judo Shinsu context remains. The dojo is a spiritual place.
By the time the Ueshiba was born the Samurai era had already been over for 20 years. Takeda is the one who really crossed over.
If you take a look at "Aiki Budo is the Way of Human Development
" you'll see that Ueshiba was hardly the originator of the concept of Budo as social and personal reform.
The word "dojo" does have its roots in Buddhism, but not specifically Jodo Shinshu.
FWIW, Ueshiba was educated in a Shingon
temple, which is quite different from Jodo Shinshu. He continued to use Shingon terminology and concepts when he spoke, even into his later years.
I'm not sure what your point is with Kamidana, but it's very common in Japanese households to have both Buddhist and Shinto accoutrements.
Dissecting the Founder's enlightenment is very tricky, even in Japanese, and technical instruction is woven throughout everything. I think that it's very difficult to try and dissect it based upon the current uncertain translations, and without a background in the context of what he was speaking about.