arXiv:2507.10594v1 Announce Type: cross Abstract: Online learning, where feature spaces can change over time, offers a flexible learning paradigm that has attracted considerable attention. However, it still faces three significant challenges. First, the heterogeneity of real-world data streams with mixed feature types presents challenges for traditional parametric modeling. Second, data stream distributions can shift over time, causing an abrupt and substantial decline in model performance. Third, it is often infeasible to label every data instance due to time and cost constraints. To address these issues, we proposed OL-MDISF (Online Learning from Mix-typed, Drifted, and Incomplete Streaming Features), which constructs a latent copula-based representation for heterogeneous features, detects drifts via ensemble entropy and latent mismatch, and performs structure-aware pseudo-labeling. This companion paper serves as a standalone technical reference to OL-MDISF. It provides a contextual discussion of related work in mixed-type modeling, drift adaptation, and weak supervision, as well as a comprehensive set of experiments across 14 real-world datasets under two types of drift scenarios. These include CER trends, ablation studies, sensitivity analyses, and temporal ensemble dynamics. We hope this document offers a reproducible benchmark for online learning on complex, weakly supervised streaming data.