With regard to your first question on alcohol and drinking Bahá'u'lláh fully aware of the great misery that it brings about, prohibits it as He expressly states that everything that takes away the mind or in other words makes one drunk is forbidden. The Master has promoted the same idea.
In connection with spiritualism, although the Master says that there is some element of truth in what some teach under the subject of auto-suggestion and others, spiritualism as such is not taught by the Bahá'í religion. Our Master has said that religion and true science must go together and most of these things have not been proved by science.
As to your third question Shoghi Effendi would like you to understand that when one believes in one to be divinely inspired and when one is convinced that he has a great mission to the world in his teachings, he must very naturally be ready to accept all that that world-teacher that divinely-inspired man says. It is with this view that he feels that a real Bahá'í would be one who is convinced that Bahá'u'lláh was a world-teacher and a Messenger of God bearing to mankind a great Message, and would therefore be ready to accept all that Bahá'u'lláh has said and the same is true of the Master whom we believe to have been the great propounder of the Bahá'í teachings and the one through whom the Covenant of God was firmly established in the world.
With regard to the differentiation between Bahá'í and Bahá'í friend. This differentiation was not one which Bahá'u'lláh and the Master firmly established but because there are so many people who are attracted to the Bahá'í Cause just as they are attracted to some society and people who have not developed spiritually to look at the world and the spiritual elements of life in the proper light that a Bahá'í would look at it, it has become a habit of differentiating between what you might call beginners in the Bahá'í Movement and those who have studied the Movement thoroughly and who know its teachings exactly and who understand the real spirit that is back of it all. You should not think, however, that a Bahá'í is one who is superior to a Bahá'í friend, but only that he has studied the Movement better and realizes well the great and divine spirit that is at the root of all Bahá'í teachings.
I hope that in spite of the briefness that has been necessary in answering your interesting questions, I have been able to explain to you properly the meaning of each answer. It is always through questioning and mature thought that we can arrive at the root of everything and in the teachings of Bahá'u'lláh there are so many things which though at present seemingly unnecessary will be of great necessity in the future development of mankind.