The best source of info would be the local Ru consulate/embassy https://mexico.mid.ru/es/seccion_consular/tramite_de_visas/visa_consular/ - maybe give them a call?
From what I see on their web site, three things may be of interest:
All foreign nationals (non-MX) must apply in person (wonder if that squashes the idea of a third-party visa agency):
(Las personas de otras nacionalidades están obligadas a tramitar sus visas personalmente);
All foreign nationals also must present their residence cards (which will become an issue if you're there just visiting):
(Los extranjeros deben presentar también su forma migratoria de residencia en México)
The service takes up to 20 business days (oh well).
With all that in mind (and until you learn otherwise from the consulate), I think you might be better off applying here in the US (it also offers shorter wait times and a pretty straightforward process, which many people on this board are familiar with and would be happy to help guide you through).
ETA: with the news of more cuts to Ru embassy personnel, maybe not such a clear cut decision when it comes to timing...but still, I'd apply here, rather than in Mexico.