The development of sustainable, intelligent food packaging has attracted increasing attention as an alternative to conventional petroleum-based plastics. This study developed multifunctional chitosan–poly(vinyl alcohol) (CS–PVA) films enriched with an anthocyanin-rich red cabbage (RC) extract and a phenolic-rich aqueous Lobularia maritima extract (AELm) and evaluated them as active and intelligent packaging materials for monitoring yoghurt freshness. The phenolic profiles of both extracts were characterised by HPLC-MS prior to incorporation into the CS–PVA matrix, and the resulting films were assessed for their structural, physicochemical, optical (visible and UV-blocking), antioxidant, antimicrobial, and pH-responsive colourimetric properties. Among all formulations, the dual-extract film (CS–PVA-RC/AELm) showed the highest ABTS (73.41%) and FRAP (82.94 μmol Fe2+/g) antioxidant activity, with a DPPH scavenging of 77.58% that did not differ significantly from CS–PVA-AELm. It also had the lowest swelling (57.44% vs 79.24% for the control), and the extract-containing films blocked far more UVB and UVA than the control (dual-extract film: UVB 92.46% vs 40.64%; UVA 83.33% vs 28.17%), although part of this effect reflects film thickness (0.20 vs 0.13 mm). The extract-enriched films showed lower MICs than the unmodified CS–PVA film against several of the tested microorganisms in vitro, with the largest reductions observed for CS–PVA-RC. The dual-extract film did not consistently outperform the single-extract films in the antimicrobial assay. The films also showed a statistically confirmed colourimetric response during refrigerated yoghurt storage (ΔE*ab = 11.62 ± 0.61 by day 14; hue angle shifting from 18.6° to 32.4°; p < 0.05), distinguishable from the RC-only formulation from day 7 onwards. Spectral analysis did not detect the characteristic signature of classical anthocyanin–flavonol co-pigmentation, suggesting that the combined functional benefits of RC and AELm more likely arise from largely independent antioxidant and antimicrobial contributions rather than a chromophore-stabilising interaction; confirming this mechanistic interpretation would require dedicated kinetic or accelerated-stability studies, which were beyond the scope of the present work. Yoghurt packaged with CS–PVA-RC/AELm showed lower lipid oxidation (0.92 vs 2.38 mg MDA/kg at day 14) and greater pH stability over 14 days (pH 4.32 vs 4.01 at day 14) than the control, suggesting potential for improved preservation performance under refrigerated storage. These preliminary findings indicate that combining red cabbage anthocyanins with L. maritima phenolics is a promising strategy for eco-friendly smart packaging with combined antioxidant, antimicrobial, and freshness-monitoring functions, pending further mechanistic and stability validation.