ISP Ring & Power Issues

So we have around 140 locations with many different providers, including Zayo, Centurylink, Level3(Legacy twtc), AT&T, Comcast, Charter, Legacy TWC, Uniti(Legacy Southern Light) and a few others.

The majority of these are serviced by a single lateral, to a CPE, normally Ciena, Adva, or Cisco, with typically a standard duplex fiber uplink, though some use BiDi. Most of those, to my knowledge, are serviced directly out of a headend or central office, meaning as long as our site has power then we should be good, because the headend or CO would have generator backup so in the event of power issues all we have to worry about is our site itself. The obvious downside of this design is if there is a fiber cut along this single path then our circuit will go down.

Several sites, including all of the legacy Level3/TWTC sites are on a ring setup. Single lateral to a CPE, but the CPE has dual fiber uplinks, meaning we could take a fiber cut on either side of the ring and still have service. They have DC batteries and a rectifier for a pretty solid uptime.

Finally we have just a few sites serviced by a decent sized independent provider, and the issue happened this week where a storm came through the city and caused many power outages. Our service went down, yet we still had local power. What we ended up finding out was multiple customers on our ring had lost power (the right combination i suppose, on both "sides" of us) and that is why we lost service.

So obviously this has posed some questions, i know they do not use DC batteries/rectifier, but did not recall if they provided a UPS to all customer sites, what the size of it was, and what the minimum uptime was. Basically they are reliant on customers power reliability and capability for the stability of their rings.

So as a customer, no matter what preparations or capacity we have (generator, etc) we could still be offline due to power issues in the area and other customers lack of said preparations, which is a bit of a downer and opens up some questions i didn't necessarily think to ask before. Luckily we had LTE backup so critical services remained functional.

So if anyone can speak from the ISP side, and other folks in a similar case from the customer side, what is your thoughts on this and what questions would you want to ask during the bidding/provider selection process to have the best comfort level with what you are purchasing?