Is it correct to say Bible has 2 eyewitness accounts (Matthew, Mark and Luke as comprehensive one & John being the other) of Jesus Christ's lifetime? Since the Synoptic problem indicates that the Synoptic gospels form a comprehensive view that gives a holistic perspective, therefore, bible readers can Not use the argument that the 3 gospels of Matthew, Mark and Luke are 3 separate eyewitness accounts of Jesus Christ's lifetime.
I emphasize can Not because if we consider all the following Hypothesis and models associated with the Synoptic gospels then we have to take into account that:
-one of the gospels was a source for the other two gospels
Or
-two of the gospels was a source for one of the gospels
Or
-one of the gospels and some other Q source(s) were a the sources for the other 2 gospels
and so on and so forth..............
Two-Source Hypothesis [Mark-Q model]
Four-Source Hypothesis [Mark-Q model with M and L]
Mark-Q Theory with Proto-Luke
Proto-Matthew (and Proto-Luke)
Proto-Mark (MkH)
Markan Hypothesis (MkH)
Proto-Secret Mark
Koester Hypothesis
Deutero-Mark (dMk)
Three-Source Hypothesis [Mark-Q-Matthew model]3SH
Farrer Hypothesis [Mark-Matthew model]
Griesbach (or Two-Gospel) Hypothesis [Matthew-Luke model]
Proto-Matthew
Traditional Augustinian Hypothesis [Matthew-Mark model]
Proto-Luke
Proto-Matthew (pMt)
Proto-Gospel Theory (UrG)
LTH: The Logia Translation Hypothesis
Multiple Proto-Gospel Theories
Mark-Luke model
Luke-Matthew model
Luke-Mark model
Luke-Q model
Therefore, Christian apologists can No longer use the argument that Matthew, Mark and Luke are 3 separate eyewitness accounts of Jesus Christ's lifetime.  
However, would it still be correct to state that?
a)Gospels of Matthew, Mark and Luke are a comprehensive view that correspond to 1 eyewitness account of Jesus Christ's lifetime
b)and Gospel of John is the other eyewitness account of Jesus Christ's lifetime
Therefore, would it be correct to say that the Bible has 2 eyewitness accounts of Jesus Christ's lifetime?
Because the Synoptic Gospels contain significant overlapping content but are not identical, we probably need to drill down one layer further.
In one sense, the claim is true: we have two Gospels written by eyewitnesses, those of Matthew &amp; John.
In a more complex sense, though, there is a great deal of eyewitness content on Mark &amp; Luke that isn't in Matthew or John. If, for sake of argument, Luke interviewed Mary (the mother of Jesus), to obtain his information about Elizabeth, the Nativity, the Magnificat, etc--then this is eyewitness testimony preserved by Luke--and only Luke.
Each Gospel contains details of the resurrection narrative that aren't found in any other Gospel (though Mark has only a smidge of unique content). Even if we set aside Mark for the moment, only Matthew tells of the soldiers guarding the tomb, only Luke tells the details of the appearance on the road to Emmaus, only John has the appearance at the sea of Tiberius, and so on. So we do in fact have more than two eyewitness accounts for some of Jesus' ministry. For the resurrection we've got at least four sources (and many would say five by adding Paul) providing independent but corroboratory evidence.
I should acknowledge that I do not believe in Markan Priority or Q, but I've certainly read thoughtful arguments by many people who do. One way that I've seen multiple attestation in the Gospels counted is:

Mark
Q
Material unique to Matthew (M)
Material unique to Luke (L)
John

And to treat each of these as independent sources. If a particular event is separately attested in all 5 of those subdivisions of source-criticism, it would be considered to be attested by 5 separate sources, not just 2.
My own theory on the Synoptic Problem (similar but not identical to the Griesbach Hypothesis) would rewrite the above as follows:

Matthew
Lukan content not found in Matthew
Markan content not found in Matthew or Luke (just a handful of verses)
John

So we can still get more than double attestation for some events.

Appendix
My own theory on the Synoptic Problem is presented here
For those who are frustrated by my extremely abbreviated claim that Matthew &amp; John were written by eyewitnesses, a much more exhaustive discussion is found in the video series I'm making here.