Electroencephalography (EEG) has found many applications cutting across many domains, such as digital health, affective computing, and human-machine interfaces. However, its widespread adoption in practice has been primarily inhibited by its susceptibility to noise artifacts and the low spatial resolution of electrodes on commercial EEG sensors. While several prior works have investigated techniques for detecting and extracting noise, our understanding of performance degradation due to electrode sparsity remains limited. In this work, we explore the feasibility of using Functional Connectivity (FC) for improving the EEG sensing-based accuracy using two exemplars downstream, working memory-related tasks: (a) cognitive task load (CTL) assessment and (b) high attentional event-evoked potential (EEP) episodes detection. This paper proposes an integrated approach, EEGAmp+, that first utilizes channel-wise functional connectivity modules using independent component analysis (ICA) coupled with cosine distance for EEG signal reconstruction for cognitive task load assessment tasks. This is then coupled with a sliding window change point detection technique paired with continuous wavelet transformation (CWT) to extract high attentional EEP episodes. Our empirical results indicate that using independent component analysis (ICA) coupled with FC to improve spatial resolution increased cognitive load assessment accuracy by [5.6% ± 1.13] across four machine learning algorithms. Furthermore, after signal reconstruction, we introduce sliding window CPD coupled with CWT, which allows us to extract EEP segments legibly through decomposing the signals and the ability to capture both time and frequency representation from the reconstructed signal boosting detection accuracy by [11.1% ±1.31].