All of these things are of the highest importance. If someone in a different stream expresses the same faith the apostles handed down to us, professing the same Jesus they knew, worshipped, and died for, then I'm calling that man or woman a brother or a sister in Christ.
I don't know any Mormons, Buddhists (my mom is a Buddhist), or Jehovah's Witnesses I would call a brother or sister in the faith. They profess a different gospel, and worship a different Jesus, unto a different end than I do. Buddhists really don't even worship God at all.
But I've interacted with many Catholics that express a deep, rich, authentic relationship with Jesus that looks nothing like the straw man produced earlier in the thread. Right doctrine - right faith in the right Jesus - produces the right fruit. We're to inspect that fruit and judge accordingly. Not from a distance, and not in religious pride.
I, for one, appreciate denominational labels and distinctives - it helps me to honor and cherish my brothers and sisters related to the distinctives they feel called to within the streams they are serving the Lord. Just had a great time with 800 mostly Baptist pastors the last few days. Not my cup of tea (related to worship style) in terms of my main assignment from heaven, but I appreciate and am blessed by what my Baptist brothers bring to the table in terms of dedication and fervency for the word of God.