"Excellent Communication skills"

This sounds like a perfect candidate to the Dunning–Kruger effect. While one might know that they are poor communicators, this does not really come up until you are out of your comfort zone.

Can you elaborate on this?

Is there a thing like over-sharing? If somebody is constantly writing walls of texts on slack or "tweeting" every 15 minutes about their progress is good thing or can this be too much?

Think of it this way. You are not in the office with the team. You need to actively do as much as possible so no one notices this. This means reading other peoples commits and PRs just to know what everyone is doing. If you had been in the office they would have probably mentioned it in conversation. If someone messages you every 5 minutes you need to discuss that so you can work, just like if someone was interrupting you every 5 minutes in the office. But again, like in the office if its work hours and someone messages you, just like if someone asked you a normal question in the office, then you should answer promptly and be on top of it. You don't wont people to not be able to get in touch with you or not know what you are doing - and this is on you to solve not them.

pludge?

Maybe plow + trudge? I've been on a few projects where that was a valid verb.

Plunge is probably what was meant.