SB replied: William Shakespeare (or Shakspere, or Shakespear, or umpteen variants of the name, which, conventionally for the times, was spelt in a variety of different ways) was a member of The Lord Chamberlain's Men, later The King's Men, who performed the plays collected in the First Folio and was positively identified as the author of them by Heminges and Condell, who'd also been part of The Lord Chamberlain's Men and The King's Men, and named in the will of William Shakespeare (or Shakespere, Shakespear, etc - see above regarding the variable spelling, typical for the day).

Ben Jonson, who'd known Shakespeare since the late 1590s, also commended him in verse. In later years, and in private conversation, with William Drummond, he more harshly criticised Shakespeare, but never once claimed that he wasn't an author, or that the name was a pseudonym that had been mixed up with another fellow, and in his posthumously published Timber again made criticisms of Shakespeare's literary failings, but again made no suggestion that the name was a pseudonym. 

George Buc, Master Of The Revels, positively identified Shakespeare as the author of King Lear in 1607.

Mark Haslett wrote: His professional contemporaries published their belief that “Shakespeare” was a pen name.

SB replied: Please provide a quote from a contemporary of Shakespeare directly and unequivocally stating that it was a pen name.

Mark Haslett wrote: Stratford Will owned no evidence of owning books. He had no evidence of education. He had no training in music, law, falconry, Greek, French, Italian...etc. etc. [note by SB - quote truncated - please see Mark's post above for the full list]

SB replied: By common consent, Shakespeare's plays do not demonstrate that they are the work of a highly-educated, well-travelled man. This was the criticism made by his contemporaries, like the author(s) of The Parnassus Plays, and repeatedly made by Ben Jonson. It was also the criticism of many critics in The Augustan Period (early eighteenth century) who much preferred Jonson.

Apart from The Tempest, Shakespeare's plays never follow the classical principle of unity of time, place and action. 

They make repeated errors such as:

Giving Bohemia a coastline;
Making Delphi an island, rather than a city;
Having King John use cannons decades before their invention;
Showing Ancient Rome having chiming clocks;
Having Ancient Egyptians play billiards;
Make Richard of Gloucester quote Machiavelli years before he was born;
Make Ulysses quote Aristotle thousands of years before he was born;

There's lots we don't know about Will, and Stratfordians have indulged themselves far too much over the years, decades and centuries. But there's lots we do know too, about him, other writers, and the times in which they worked - and none of it supports the notion of unhappy coincidence or conscious conspiracy in which the true author, using the pseudonym "Shakespeare", found their work unfairly attributed to another fellow with the same name.

From "To the memory of my Beloved the Author, Mr William Shakespeare": And though thou hadst small Latin and less Greek.

From his conversation with William Drummond: [Note from SB - this is among a series of other aspersions cast by Jonson at other writers]

That Shakespeare wanted art. 

[NOTE from SB - this is in reference to The Winter's Tale] Shakespeare in a play brought in a number of men saying they had suffered shipwreck in Bohemia, where there is no sea near by some hundred miles.

From De Shakespeare Nostrat, in Timber: "I remember the players have often mentioned it as an honor to Shakespeare, that in his writing, whatsoever he penned, he never blotted out a line. My answer hath been, “Would he had blotted a thousand,” which they thought a malevolent speech. I had not told posterity this but for their ignorance, who chose that circumstance to commend their friend by wherein he most faulted; and to justify mine own candor, for I loved the man, and do honor his memory on this side idolatry as much as any. He was, indeed, honest, and of an open and free nature; had an excellent fancy, brave notions, and gentle expressions, wherein he flowed with that facility that sometime it was necessary he should be stopped. “Sufflaminandus erat,” as Augustus said of Haterius. His wit was in his own power; would the rule of it had been so too. Many times he fell into those things, could not escape laughter, as when he said in the person of Cæsar, one speaking to him: “Cæsar, thou dost me wrong.” He replied: “Cæsar did never wrong but with just cause; and such like, which were ridiculous. But he redeemed his vices with his virtues. There was ever more in him to be praised than to be pardoned.

SB replied: The stationer's register records on 26 November 1607 that Sir George Buck attested that King Lear was the work of William Shakespeare, and that the play had been performed at court.

Mark Haslett wrote: Hall was categorically and provably not referring to Marston

SB replied: You haven't provided anything that categorically proves this.

Mark Haslett wrote: William Shakesper, the glover’s son 

SB replied: What does John Shakespeare's trade have to do with William Shakespeare's writing?

SB replied: There are no "double meanings" in the statements I've provided. Why would there be? All three were made after Shakespeare was dead, and even longer after Oxford's death (assuming that you're positing him as the true author). The conversation with Drummond was made in private, and Timber was published posthumously.