As always with Mexico, I highly recommend seeking out people who are currently living in the places that you want to visit. Speak to the locals living in those places and find out how you can better integrate. Ask questions, be curious and kind. For updates about Mexico City, as always I recommend following Ubish Yaren on Instagram. You can also follow Anais of The Curious Mexican for updates on the restaurant and food scene in Mexico City and what is back open.
For updates about what's going on in Oaxaca, Susan of Brooklyn Tropicali has been sharing her updates of what's going on around the city and state of Oaxaca. Trisha of PS I'm On My Way currently lives in Cabo San Lucas and can share some insights into what is happening there with you. Check out her website here. She also has a great Mexico-specific website called Mexico Insider which you can read here. For regular updates about life in Merida and around the Yucatan, check out Mexico Cassie who has also recently written a fantastic guide about Traveling Yucatan with Kids. Shelley of Travel Mexico Solo also shares her experiences in Merida and around the Yucatan. She also has a fantastic blog all about Merida here and all about Oaxaca here. The Yucatan Times is the local English newspaper in Merida that shares local updates and news reports. To keep up with what's going on in and around Guadalajara, follow Alex of the Backpacking Brunette. Vallarta Daily is the local English news there where you can learn about any changes in the situation in Puerto Vallarta and the surrounding Nayarit beach towns as well. Unfortunately, this has been purchased by Mexico New Daily and all articles now sit behind a paywall, but if you are living in Vallarta, then it may be a subscription you want to consider.
Riviera Maya News is the local English newspaper there where you can keep up with changes. I believe this is the region that is changing the most in regards to safety at the minute and if you plan to independently travel here (renting a car and exploring without tours or away from resorts), then I highly recommend speaking to someone who is there right now.
As always, a great place to keep up to date with news about what's happening all over Mexico in English is Mexico News Daily. It seems that if you register as a user (for free), you are able to see more articles at the moment. | 
