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A rich system of thousands of compact stellar systems (CSSs) including globular clusters (GCs) comma nuclear star clusters (NSCs) comma ultra-compact dwarf galaxies (UCDs) comma and compact elliptical galaxies (cEs) permeate the nearby (16.7 Mpc) Virgo galaxy cluster. CSSs are very useful as they are observationally easily accessible comma and effectively trace the descendants of former diffuse systems disrupted in violent galaxy cluster environment. CSSs have interconnected (often galactic) formation histories comma and - in a growing number of examples - have recently been found to harbor super-massive black holes (SMBHs) comma confirming their utility in representing remnant nuclei of formerly more massive galaxies tidally stripped of their outer stellar sheaths. These discoveries imply that CSSs may represent a rich population of targets in which to search for so-called d_commaintermediated_comma-mass BHs (IMBHs) - a class whose demographics are generally V1.0. A systematic search for massive BHs in CSSs in a cluster environment has been prohibitively expensive using current ground- or space-based facilities however comma this opportunity has been opened up with the imminent launch of JWST comma on which >40 hours were awarded in Cycle 1 to conduct such a search. Here we propose preparatory HST+ACS-WFC3 observations to obtain high-resolution imaging for a small number of the planned JWST targets for which archival HST imaging is not available. These images will be crucial in maximizing the scientific value of the upcoming JWST observations by enabling the construction of 3D de-projected CSS luminosity profiles comma a necessary component for stellar dynamical modeling and meaningfully constraining central BH properties.