Q1. When we worship Lord Vishnu, he is worshipped along with his merciful consorts Sridevi and bhudevi. In most of the South Indian Vaishnava temples this is the tradition. So why we do not worship Lord Nityananda with his divine consorts Vasuda devi and jahnavi devi. Similarly why we do not worship Lord Chaitanya accompanied by His divine consorts Laxmipriya and Vishnupriya?
A1 by SG. We do worship Shri Shri Jahnavi Nitai and Shri Shri Vasudha Nitai. Shrila Bhaktivinoda Thakura ended the Chapters in his holy book Hari Nama Chintamani by seekings the blessings and shelter of Shri Shri Jahnavi Nitai. You will note that in the 12 Holy Names of Lord Nityananda which you are chanting daily, the Holy Names of Lord Nityananda in relation to Shrimati Jahnavi devi and Shrimati Vasudha devi are glorified. So by chanting These 12 Holy Names daily you are worshiping Jahnavi Nitai and Vasudha Nitai. One can also worship Them in Deity like They are in Shri Ekachakra Dhama.
Q2. When we are offering guru pranams starting with "Vandeham", according to my imperfect understanding there is no specific prayer addressing Lord Nityananda. Since Lord Nityananda is considered to be the original spiritual master, would it be appropriate to add a prayer before addressing Lord Chaitanya with "Namo maha vadanyaya" prayer.
"I offer my prostrated obeisances to the Supreme Servitor Lord Nityananda Prabhu, who is the awarder of the topmost joy and happiness to all living entities and to all our senses, the bestower of the Holy Name of Lord Gaura-Hari, and the crest jewel of all paramahamsa mendicants."
nityanandam aham vande, karne lambita-mauktikam chaitanyagraja-rupena, pavitri-krta-bhutalam
"I offer my prostrated obeisances to the Supreme Servitor Lord Nityananda Prabhu, on whose left lotus ear a pearl ornament is swinging. Accepting the role of the elder brother of the Supreme Personality of Godhead Lord Chaitanya Mahaprabhu, Lord Nityananda completely purified the entire earth by the the pollen of His lotus feet."