Kontakt is a sampler/sample player. Depending on the product, you might only need the free version (Kontakt Player). Others require the paid version (Kontakt Full). Some might run in a proprietary sample player.
I don't know if you'll find much that has a vintage option, there are only a few niche options that I can think of that have that specifically.
I would encourage you to poke around the websites of these companies to see what else they offer, and definitely listen to the audio demos. I've picked out ones that are smaller sized ensembles or offer divisi options.
Keep in mind that most of these products are recorded in sections - Violin 1, 2, Viola, Cello, and Bass recorded separately and therefore must be played in separately unless there is an ensemble patch.
Spitfire Abbey Road Two - string quintet. Has a vintage mic mix. Runs in their player. Upgraded version has more articulations and microphones.
Spitfire Chamber Strings Essentials - string sections. Runs in Kontakt Player. Upgraded version has more articulations and microphones.
Spitfire Studio Strings - string sections. Runs in Kontakt Player. Upgraded version has more articulations and microphones.
Orchestral Tools LA Sessions - string sections. Runs in their player. You can also purchase the strings separately from the full package.
Audiobro LA Scoring Strings - string sections with divisi options. Runs in Kontakt Player.
Audiobro Modern Scoring Strings - string sections with divisi options. Runs in Kontakt Player.
Pulse Audio Vivid Strings - string sections. Runs in Kontakt Full.
Invalid Link Removed - string sections. Runs in Kontakt Player.
Native Instruments Session Strings - string ensemble. Runs in Kontakt Player. Upgraded version has sections.
This is by no means an exhaustive list, but a place to start. Good luck!