Complicated.
The answer is both yes and no.
Jehovah’s Witnesses believes that Jesus is Michael the Archangel which is absurd and they also believe that Jesus didn’t fully resurrect in flesh but they believe that only his soul resurrected. Jehovah’s Witnesses also believes that all other Christian denomination is false and that they would eventually all die in the last days. They believe that Jesus died on a wooden pole instead of a cross.
Mormons (LDS) tends to pretend that they are normal Christians but obviously they’re not. They even have other scriptures such as the Book of Mormon, Pearl of Price, and other books they have out there. They also believe that Joseph Smith was a genuine prophet. They believe that ancient Jews built boats and sailed to America, and those Jews are later ancestors of Native Americans, that Jesus went to America after his resurrection, that Jesus and Satan are brothers, they also believe that God has a wife (heavenly mother) and that they had countless celestial sexual relations which brought us to life, they believe that God actually had sex with Mary (like LITERALLY), New Jerusalem would be in America, belief that there are 3 heavens, and etc. Mormons have a Mormon temple where they do crazy things like baptism for the dead, getting secret new spiritual names, learning secret hand shakes that they will do with the angels, temple endowment videos which features: Jehovah God becoming Adam, Elohim the God not knowing how he created the world, and other absurd stuff.
Very luckily for them, the criteria of being saved is accepting Jesus as the Lord and Savior so I guess some (or many) of Mormons and Jehovah’s Witnesses might be saved although there will be consequences for holding on to some very crazy doctrines. I know that lots of Mormons and Jehovah’s Witnesses are good people and I have no intention of demonizing them.
Will they be saved? I guess so but not sure…
Are they true Christians? No. They are false Christians.