what links:
1: Osbourne; Dio; Gillan; Hughes; Gillen; Martin?
2: Droeshout, Chandos, Cobbe and Grafton portraits?
3: Pied Piper poet; hometown of the Simpsons; male horse under the age of four?
4: Braunschweig; Scotland; Queen Victoria's father?
5: Gala; Honeydew; Cassaba; Cantaloupe?
6: Alexei Peshkov (writer) and Vosdanik Adoian (artist)?
7: Constance Markievicz; Nancy Astor; Margaret Wintringham?
3: Pied Piper poet; hometown of the Simpsons; male horse under the age of four? These is Guns. Browning machine gun, Springfield rifle, and Colt 45 revolver beloved of all authentic gunslingers.
4: Braunschweig; Scotland; Queen Victoria's father? This a bit of a trick question, wot I needed some help from Auntie R. Queen Victoria's father was Prince Edward, a son of George IV. He was a commander in Canada when in the Army, and Prince Edward Island (now a Province wot produces 33% of Canada's potatoes) was named after him. It just so happen that there 2 other Maritime Provinces in Canada wot fit this list - Nova Scotia and New Brunswick. So I do say it Canadian Provinces.
7: Constance Markievicz; Nancy Astor; Margaret Wintringham? I know Nancy Astor the first woman to take her seat in the House of Commons, and I think Constance Marlievicz the first to be elected but did not take her seat. So Margaret Wintringham the third woman to be elected to the House of Commons.
1: Osbourne; Dio; Gillan; Hughes; Gillen; Martin?
some of Black Sabbath's lead singers over the years [been quite a bunch, eh?]
2: Droeshout, Chandos, Cobbe and Grafton portraits?
portraits possibly depicting Will Shakespeare
5: Gala; Honeydew; Cassaba; Cantaloupe?
the last three are melons... gala is a type of apple, however, if you add an "i", galia is also a melon.... so I vote for melons...
Ohhh whoops, typo there. But it didn't faze our Asy 
Melons are STPD;s breakfast of choice 
though she will be getting Dorset Cereals when next home! 
well done both 
6: Alexei Peshkov (writer) and Vosdanik Adoian (artist)?
both took the name GORKY