Multicultural urban societies face continuing challenges in reconciling cultural identity, intercultural communication, and social integration, while existing research has often examined these dimensions through separate individual, relational, and institutional perspectives. This study investigated their interrelationships through a qualitative comparative documentary analysis of Indonesia, Malaysia, and Singapore. A purposively assembled corpus of 33 scholarly and institutional sources was examined according to conceptual relevance, geographical applicability, and documented evidence concerning multicultural interaction. The analysis employed a common thematic framework covering identity recognition, multiple identification, language negotiation, communication competence, intergroup contact, civic belonging, institutional support, and everyday interaction settings. Within-case examination and cross-case comparison identified recurring patterns and institutional differences without treating qualitative classifications as population-level measurements. The findings indicated that cultural identity continuity was not inherently incompatible with civic participation, although their coexistence was conditioned by social recognition and opportunities for inclusive interaction. Communicative adaptation, reciprocal contact, and cooperative relationships emerged as recurrent themes associated with intercultural engagement rather than independently verified causal mechanisms. Comparative coding indicated differences in the relative prominence of community mediation, multicultural governance arrangements, and institutionalized contact across the three countries. Formal multicultural recognition also remained analytically distinct from everyday intercultural practices. The study contributes a conditional conceptual synthesis of plural integration that connects individual identification, relational competence, and institutional participation. Its explanatory scope is limited by the heterogeneous documentary corpus and the absence of primary empirical measurement.