England had an abundance of trade and agriculture so was very wealthy. It even had a coinage economy. This encouraged people to rival for the throne.
did Edward have any relations suitable to become heirs to the throne
Edward had no children. Edgar Aethling was his only male blood relative but was very young (14) and lacked support of English earls.
More than one successor named by Edward
King for over 20 years so probably named more than one successor throughout his reign. Both William and Harold claimed Edward had identified them.
William's claim
Duke of Normandy. Said that Edward promised him the throne in 1051. Harold swore an oath on holy relics in support of this. William claimed Harold was an oathbreaker when Harold became King after Edward died- gained Papal support. Was a distant cousin of Edward's.
Harold's claim
Earl of Wessex and head of wealthiest and most powerful family in England. Brother-in-law to Edward. Had the support of the Witan. Anglo Saxon Chronicles state that Edward named Harold as his successor on his deathbed.
Harald's claim
King of Norway. Respected Viking warroior and descendant of past king of England, King Cnut. Encouraged by Tostig, Harold's exiled brother.