Yes, I did know that the JW’s and the SDA"s had the same origins in the Millerite movement, but I did not know they believed Michael was another name for Jesus Christ in the Bible in some instances–that was a new one on me, but they do not believe that the Archangel Michael, a created being, is God. However, the do have the correct Trinitarian beliefs, and they baptize with water, so I see no reason their Baptism would be invalid.
I have never heard an SDA mention or talk about this–they seem to emphasize more their end-times prophecies and their Sabbath worship, and even “soul sleep”, but the JW’s are another matter–they are not Trinitarian and do not believe Jesus is God, so their baptisms
are invalid.
The SDA’s most likely can be properly called a Christian denomination, while the JW’s can not. They have denied the basic concept of the Trinity and the divinity of Jesus.
There is an SDA church about 2 or 3 blocks from me–i would love to go to one of their Sabbath services just to hear one of their prophecy preachings and see what the service is like, but I really don’t want to get involved. There is no danger at all I would be persuaded of anything heretical. i survived a fundamentalist family, pentecostalism and evangelicalism
without a scratch to my Catholic beliefs, but I did gain a greater understanding of the value of Sacred Scripture, and I am grateful for that.