At the risk of incurring the not inconsiderable displeasure of JC & Co. who have eloquently listed out many differences between the 2 Brahmo Samajes, I would also like to list out the points on which we agree.
1.ONE GOD. ie. a Singular Author and Preserver of Existence
2. Brahmos reject scripture as authority.
3. Brahmos reject prophets, gurus, messiahs, or avatars.
4. Brahmos denounce idol worship and polytheism
5. Brahmos are against distinctions like caste
Beyond this it would be very difficult to generate consensus between Adi'ism and Sadharn'ism.