Haifan Bahais say they believe Abdul Baha has a lesser status than Baha'u'llah, but in practice Abdul Baha's status is greater. First he is the one whose picture Bahais hang up in their houses, not Baha'u'llah. And whenever Abdul Baha and Baha'u'llah conflict, Bahais side with Abdul Baha. For example, Haifan Bahais consider bigamy to be forbidden because Abdul Baha said it was forbidden in communications with Western believers, even though Baha'u'llah permitted bigamy. So it seems that whatever infallibility Abdul Baha has is even greater than the Most Great Infallibility, in the view of Haifan Bahais.
We don't hang a picture of Baha'u'llah in our houses because Baha'u'llah is too exalted to be put into public view. The monogamy decision of Abdu'l-Baha is based on His interpretation of Baha'u'llah. This note in the translation of the Aqdas is best in explaining Abdu'l-Baha's interpretation and also why Baha'u'llah appeared to be permitting two wives:
89. Beware that ye take not unto yourselves more
wives than two. Whoso contenteth himself with
a single partner from among the maidservants
of God, both he and she shall live in tranquillity. # 63
While the text of the Kitáb-i-Aqdas appears to permit
bigamy, Bahá'u'lláh counsels that tranquillity and contentment
derive from monogamy. In another Tablet, He
underlines the importance of the individual's acting in such
a way as to "bring comfort to himself and to his partner".
Abdu'l-Bahá, the authorized Interpreter of the Bahá'í
Writings, states that in the text of the Aqdas monogamy is
in effect enjoined. He elaborates this theme in a number of
Tablets, including the following:
Know thou that polygamy is not permitted under the law of
God, for contentment with one wife hath been clearly stipulated.
Taking a second wife is made dependent upon equity and justice
being upheld between the two wives, under all conditions.
However, observance of justice and equity towards two wives is
utterly impossible. The fact that bigamy has been made
dependent upon an impossible condition is clear proof of its
absolute prohibition. Therefore it is not permissible for a man to
have more than one wife.
Polygamy is a very ancient practice among the
majority of humanity. The introduction of monogamy has
been only gradually accomplished by the Manifestations of
God. Jesus, for example, did not prohibit polygamy, but
abolished divorce except in the case of fornication;
Muhammad limited the number of wives to four, but
making plurality of wives contingent on justice, and
reintroducing permission for divorce; Bahá'u'lláh, Who was
revealing His Teachings in the milieu of a Muslim society,
introduced the question of monogamy gradually in accordance
with the principles of wisdom and the progressive
unfoldment of His purpose. The fact that He left His
followers with an infallible Interpreter of His Writings
enabled Him to outwardly permit two wives in the Kitáb-i-Aqdas
but uphold a condition that enabled 'Abdu'l-Bahá to
elucidate later that the intention of the law was to enforce
monogamy.
en.wikipedia.org
The Baha'is are clinging to their doctrines and trying to stay unified but it is not going to work because some people think for themselves.