The 1920 census lists Florence 4 years 8 months born to Edward and Matilda. Florence's obituary is on line now as Florence Burrell Murdich of Dover, Delaware. It confirms that Matilda is Matilda Hickland. Matilda emigrated in 1902 with a Burrell paying passage. Edward had died by the 1940 census and Florence was still with her mother.
If Frank was born in 1880, he is undoubtedly the boy who died in 1883 near Lurgan.
David Burrill (note the spelling) is in the 1920 NY census with wife Minnie and daughter Gladys. As cousin George Abraham b 1897ish is with them, this is probably your David. Possibly this is George from an Annoliste family, but there is a second possibility in the area. Do you have Margaret's father's name?
Robert is probably Robert David b 1887 per the 1940 census with wife Minnie and children Gladys, Thomas, and Muriel, again in NYC. That is more of a guess than the others. I will look for immigration records.
Do you have any ties to Thomas Burrell who married Elizabeth Rowan?