trademark would not apply unless the development was obviously commercial.
it is also possible to have a small amount of income for the name, if it is just to cover costs, hosting, etc. this has been normal precident, in previous big cases.
its up to you an how good your defence strategy is.
mysedo could be used as an information source, about sedo.or even critical articles. as long as u dont start selling domains, u would be ok.
trademark law is not applicable for non profitable ventures.
if i had microsoft.us , made no money from it, and provided a news service regarding new microsoft developments, they would have a hard time taking it .
rememebr must prove 3 things at arbitration.
1 of them they would fail straight away if it is non profitable . even they get 2 out of 3, they wont get domain