This summary is drawn from the Rebbe's letters to him (about 5716–5720, 1956–1960); I did not find a published biography.
Communal work. The Rebbe encouraged detailed reporting on communal activities as an expression of Ahavas Yisrael, since it inspires others (IK 5998), and suggested publicly displaying the names of participants in Torah classes to encourage involvement (IK 4001). Decisions about communal prayer spaces must consider local needs and preserve peace (IK 4403).
Influencing others. A gentle and pleasant approach yields far greater results than harshness (IK 4611).
Questions. The Rebbe clarified sources for particular prayer customs while stressing unity and peace in the shul (IK 4425), and explained that, according to the Zohar and its commentaries, Gehazi does have a portion in the World to Come (IK 7303). On Elul's special spiritual energy and its connection to redemption, see IK 6464.
Sources: the Rebbe's letters cited above.