Seeking rational workflow to reduce image-resized-file bloat in Media Library

FYI, I'm a WP novice, but a pro in image processing, so I know enough about resizing and maximizing compression to handle this before upload. Others using blogs on my multisite network may not be so well versed, so I want to rely on intelligently configuring WordPress fallback upload-resizing behavior.
I've been searching forums here and abroad for a succinct but comprehensive treatment of the technical details underlying Media Library management. Here's what I've found. Please illuminate any errors I've made.

Uploads to the Media Library (and imports via a plugin such as Add From Server always copy the file into the wp-content/uploads/YYYY/MM (or, for multisite, wp-content/uploads/site/sitenum/YYYY/MM) dir. If I want to impose a heirarchical dir structure to categorize my files, I have to use a plugin designed for this purpose.

I've resigned to using the default date-based dir structure and am testing Media Library Assistant as an alternative method of imposing organization via categories and tags metadata. I hope this will provide maximum compatibility across the platform and other plugins yet still allow me to find assets easily -- at least while working within WP. I'll rely on other tools on the server (shell commands, etc) to find files by name across multiple sites. Advice on any other notable utility plugins which may assist with advanced Media Library management is sought and appreciated.

Upon import/upload into the Media Library, image assets are going to be duplicated and resized to several size breakpoints by WordPress. Three size breakpoints (thumbnail, medium, and large) are WP defaults and these specific sizes can be confgured in Settings->Media. Additional breakpoint sizes may be defined by the theme or plugins.

Are these statements accurate? Do you have any suggestions for a plugin or image size management technique which would allow me to remove (or prevent formation of) breakpoint sizes on a per-image or per-batch basis? For example, I might upload an image which I'll always use only a single size of in my theme (Upfront), thus I have no use for alternate sizes. I would expect compatibility with MLA Categories & Tags because I'm guessing they reference an image ID in the database which all of the additional sizes also refer to -- any good resource which explains the technical details of this whole process would be nice to find, so suggest away if you know of any.
Also, I see the generated breakpoint images have filenames which are suffixed with the size (i.e. '-1024x884'), which is the same practice I use. Do you know whether WP uses this (or cares). My guess is that it relies on a size entry in the database tied to the image file name and never refers to the name to determine size after the image is entered into the database.
I appreciate all suggestions, clarifications and other resources you may provide me.
Thanks.... mark