a name commonly used in old plays for a valet or man-servant. Probably a Merry Andrew is simply the mirth-making Andrew or domestic jester. (See Merry Andrew.)
Similarly, Abigail is used in old plays for a waiting gentlewoman. (See Abigail.).
I should think of shallows and of flats, And see my wealthy Andrew docked in sand.
The “adoration of the cross” means his fervent address to the cross on which he was about to suffer. “Hail, precious cross, consecrated by the body of Christ! I come to thee exulting and full of joy. Receive me into thy dear arms.” The “flagellation” means the scourging which always preceded capital punishments, according to Roman custom.
St. Andrew's Cross
According to J. Leslie (History of Scotland), this sort of cross appeared in the heavens to Achaius, King of the Scots, and Hungus, King of the Picts, the night before their engagement with Athelstane. As they were the victors, they went barefoot to the kirk of St. Andrew, and vowed to adopt his cross as their national emblem.
(See Constatine's Cross.)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894