The date that a match is played is not included in the response from the "Stats - Halo 5 - Match Result" Endpoints. However, the Match Completed Date is included in the response from the "Stats - Halo 5 - Player Match History" Endpoint. You're probably already using the Player Match History Endpoint to retrieve the Match IDs that you feed in to the Match Result Endpoints. If you need to determine the Match Started Date, you can subtract the Match Duration from the Match Completed Date.
Unfortunately, there currently isn't a way of accessing Spartan Company information via the Halo API. The recent thread "Spartan Company Functions?
" was also inquiring about this information. This information should be made available very soon - stay tuned.
Hopefully this covers everything. Thanks for your interest in the Halo API!