[Read the whole of the 'Bacchus' scene here.]

My candidate for Bacchus is Sir John Perrot.

In 1592 Sir John Perrot was much in the news, as he faced trial for treason. Commonly reputed to be a son of Henry VIII, whom he resembled in build and manner, Perrot was a soldier and administrator, high-handed and 'habitually a coarse speaker'. (Handover, p.83) While Lord Deputy in Ireland he clashed violently with the chancellor, Adam Loftus, Archbishop of Armagh and Dublin, who sent his chaplain to confer about the Perrot problem with Sir Christopher Hatton. (Sir Christopher disliked Perrot, allegedly because Perrot had seduced an illegitimate daughter of his.) The chaplain Loftus sent was Richard Bancroft, who became first Hatton's and then Whitgift's chaplain.

Although accused of treason Perrot was in Burghley's lenient custody for some time (he was on good terms with Burghley) before being transferred to the Tower: at his trial the only charge that seemed to be pressed vigorously was that of contemptuous speech against the Queen ('a base, bastard, pissing kitchen woman'). His chief enemy Hatton being dead by the time the case came to trial, and with both the Cecils and Essex anxious to get him off - his son was married to Essex's sister - it has always been difficult to understand why Perrot was nevertheless sentenced to death. Sentence was never carried out, however. Elizabeth allegedly scoffed at the judges' guilty verdict, delayed signing the warrant and Perrot died suddenly in custody in the Tower in September 1592.

Described as 'god fatbacke', and 'god barrell-bellie', Bacchus also has a paunch 'built like a round church'. I have seen no portrait, but Perrot apparently shared a strong resemblance to Henry VIII. Presumably this included his striking physique.
Bacchus is amazingly disrespectful, not only using 'thou' constantly to his lord but conspicuously failing to give him any honorific at all. He usually addresses him as 'Summer', or at one point tipsily 'Sim Summer'. At another he drunkenly scolds and berates his lord: 'thou art a bad member, a Dunse, a mungrell...' Perrot was convicted principally on charges of speaking contemptuously of the Queen, calling her 'silly woman' and 'base, bastard pysskitching'. Camden wrote: 'He was charged first to have violated the Queenes Majesty by opprobrious words, and to have said shee was illegitimate, fearefull, and curious, that she cared not for military men, that she had hindered him from reducing Ulster into order, and that shee would one day stand in neede of his helpe.'
Bacchus implies Summer is impoverished ('a good fellow is a good fellow thou he haue neuer a penny in his purse') and stingy ('thy niggardly habitation'). Perrot had claimed the Queen's failure to send him sufficient funds had prevented his pacifying Ireland.
At one point the servant Bacchus actually addresses his monarch as 'brother':

'Nay, soft, brother Summer,...'

Perrot was widely believed to be an illegitimate son of Henry VIII. After the verdict was announced he spluttered that surely the Queen would not let her brother die.
Summer's verdict is:
'Hale him away, he barketh like a wolf; It is his drink, not hee, that rayles on vs'
This lofty tolerance fits the attitude Elizabeth adopted in public. As Camden puts it in his annals for 1592, after sentence was passed she did not sign the warrant: '... the Queenes displeasure being asswaged. For in this time shee was often heard to commend that rescript of Theodosius, Honorius, and Arcadius, If any man speake ill of the Emperour, if of lightnesse, it is to be contemned; if of madnesse, to be pittied; if of injury, to be remitted. ...

It's also worth pointing out that wolves were associated with Ireland.

Bacchus is an aggressive drunk. He threatens to urinate on Autumn and forces Will Summer to swallow a whole jack of beer on his knees. His speech is sometimes garbled and he seems over-loquacious:
'It is wine's custom to be full of words...' sighs Summer
Nothing I have seen so far says Perrot was an alcoholic, though he seems to have been a hard drinker from his youth. But his shambling replies at his trial, his complaint that his memory was failing, his brawling behaviour and recklessly disrespectful speeches in Ireland suggest his judgement had declined, and drink may have contributed. He died suddenly in September 1592 and Tennison suggests he may have been poisoned. If 'Bacchus' is a portrait of Perrot, I would guess the poison came in a bottle and was self-administered.