Gray was the only one of the quartet to play in a Test against Australia in 2013 - a 12-minute cameo in the crucial 41-16 victory in Sydney which sealed the series win - but all four will look to play a starring role in Scotland's campaign which begins on September 23 against Japan.
And Cotter admits he is already excited about putting the squad through their paces.
"Physically we'll be working very hard to find peak form. We know that teams play better in the Rugby World Cup, and we want to be one of those teams," said Cotter.
"There are a number of players we've spoken to who will be working on things with their clubs and looking for form, and may well feature in our warm-up games as a chance to push for selection.
"We have four matches before the tournament; four 80-minute spells in which we can practice our combinations and work our plays, in attack and defence, providing opportunities for a number of players to compete for a place in the final 31.
"Every team entering the Rugby World Cup wants to win, but to win a World Cup you first have to qualify from your pool, and that's our major focus: two games in five days [Japan and USA] followed by another in six [South Africa] and another in seven [Samoa]."
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