That's ok, I'm the same way with mobile devices.
I'm not a veterinarian or certified bird expert, just a disclosure. Hard to say without autopsy or testing. But the two deaths could be related to the duck bringing some microorganism that your flock at home is not familiar with (not showing signs of illness, thus being a "carrier"), of course the deaths could also have been coincidental (the RIR suffocating to death/overheating/stressing under ice cream bucket and the banty hen for some other unrelated cause). If you have other birds, it might be late, but aside from keeping an eye on whether they are behaving normal or sickly. I would suggest cleaning out feeders,etc and separating sick birds from healthy. Maybe adding some electrolytes (can be founds at
TSC or feed stores in small packets) to their water may help?
For future, I practice biosecurity by introducing my birds in stages: 30 days of quarantine in an area far/separate from my flock to observe for illness, then I put them in the coop divided by fencing/screen to get familiar, and then let them during the day interact to make sure there are no signs of aggressiveness. Sometimes this means removing my most dominant hen/rooster/drake to a separate enclosure so that it throws of the "pecking-order". This may be more info then you need.
Is the duck dominant or aggressive? I'm not sure if keeping the duck separate. Ducks can be aggressive/dominant too or if the duck (if drake) mounted the banty hen and suffocated her.
Here's a link from another backyardchicken poster about bio-security and additional information that might help.
https://www.backyardchickens.com/a/biosecurity-for-the-rest-of-us
Good luck.