In fact, isn’t NCC more mainline? The smaller evangelical denominations such as the Evangelical Covenant, Baptist General Conference, etc aren’t listed on there. And I wouldn’t touch those with a ten foot pole.
Yes, the NCC is primarily mainline (or old line) churches who are post-Christian in theology and liberal in practice. Not being on the list is not necessarily the sign of a solid church, but being on the list is the sign of a church from which one should flee.
The World Council of Churches also helpfully provides a list of bodies to avoid:
http://www.oikoumene.org/en/who-are-we/organization-structure/member-churches.html