A quick update:
I'm starting to use the third proxy provided by @HenryCooper , i'm going at the rate of adding two new proxies to my massplanner per day, i will speed things up as i get more confident.
so far, all three proxies seem good. but there may be some incompatibility with massplanner's proxy manager though.
pls see attached
the proxies work well, in the sense that i can access instagram using MP's embedded browser, and i was able to verify my accounts.
however, in MP's proxy manager, they show as "Proxy Error", but i know the proxies are working.
it's possible that Henry's proxy are not compatitible with the proxy checkers used by Massplanner's software, but they work nonetheless
i think the issue is the same as described here
Henry has explained the case here