John 4:2 (NKJV)
[SUP]2 [/SUP](though Jesus Himself did not baptize, but His disciples),
Jesus told his disciples to make disciples,
Matthew 28:19 (NKJV) Go therefore and make disciples of all the nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit,
As you just showed with your quote of Mark 1:8, Jesus baptizes with the Holy Spirit, but the disciples (including John the baptizer) can only baptize with water, and Mat. 28:19 Jesus commissioned the disciples to make disciples, He did not say "Go therefore and ill make disciples of all nations, baptizing them"
You have proven that water baptism is the one salvific baptism of Eph 4:5, but remember, like faith alone wont save you, neither will baptism alone.