The Cakewalk Studio Instruments - String Section is something you already have. Have you tried that yet? If that doesn't cut it for you, read on...
From that list you provided, I do have all 3 of the Sonivox Orchestral Companions. They sound good, but I think that the freebie
Virtual Playing Orchestra below can sound as good, and has more solo instrument options, along with sections. Some brass patches offer velocity layers and dynamic cross fades. All instruments include a general purpose articulation called “Normal-mod-wheel”. This is effectively a sustain patch with a fast attack, but the mod wheel reduces the rate of the attack.
If I was going to spend money again, I would probably have opted for Garritan Personal Orchestra, because it uses the multi-timbral Aria player. So it can have up to 16 parts in one plugin instance. Or maybe Miroslav Philharmonik CE from IK Multimedia. Those are probably good entry level orchestral libraries, with multi-timbral setups, for a reasonable price.
But before spending any money, be sure to check out the free orchestral library for the
sforzando player,
Virtual Playing Orchestra. It has been curated from the best free orchestral samples available. The
sforzando player is a single timbral player based on the same Aria engine used by Garritan.
Virtual Playing Orchestra is a free, sfz format, sample library that attempts to emulate multiple articulations of the solo and section instruments from a full orchestra using the best samples from
Sonatina Symphonic Orchestra,
No Budget Orchestra,
VSCO2 Community Edition,
University of Iowa,
Philharmonia Orchestra and extra samples from
Mattias Westlund, author of Sonatina Symphonic Orchestra.
>> http://virtualplaying.com..tual-playing-orchestra/ sforzando :: Free SFZ Player - get this to play the free orchestra!
>> http://www.plogue.com/products/sforzando/