New Zealand's tournament opens in Yokohama on Saturday against old rivals South Africa – a game regarded as the highlight of the first weekend.
Foster said with Ryan Crotty, Anton Lienert-Brown, Jack Goodhue and Sonny Bill Williams they had players in the midfield who had played a lot of Test rugby in the past four years albeit in different combinations.
"We actually like where we're at," he said.
"Whichever combination we pick we know they've been tried under the heat of battle. We know we've got different skill sets there and we kind of like the options that we've got.
"So whilst we haven't got two players that have played every Test match leading into the last two or three years, and I guess people want to feel safe about that, but I like the situation we're in. We've got proven combinations," he said.
Foster said rumours Williams was going home were wrong and he would be available for selection based on his progression from the Tonga game.
"He's trained really well and I think we said last week we've got a progression plan for a number of the guys who brought niggles into the week and overall came through it pretty good.
"Everyone was training nearly at 100 percent in the last training session and it was disappointing that 'a mischievous person has tweeted something with no information behind it'," he said.
Concerns with the surface at the Yokohama venue for their opening game with South Africa were raised when the All Blacks played there 12 months ago. Foster said they hadn't seen the ground since but dealing with what was put in front of you was one of the requirements of playing in a World Cup. At the same time, he said, he was sure Japanese authorities would have been working hard on the ground concerned.
Asked if it was ok for the All Blacks to lose to South Africa, Foster said it wasn't.
"We all know the importance of the game and that doesn't mean you're finished if you don't get the result, of course it doesn't, it's a tournament. But that's not the way we're thinking.
"We're thinking this is an outstanding opportunity to go in there and test ourselves straight away in this championship," he said.
Under coach Rassie Erasmus, who took charge of South Africa in 2018, they appeared to have brought into a plan of defence first and they had taken confidence from a system that helped prevent their opposition from attacking well.
"They've done that well and there's been some awesome games. I don't agree they've had the wood on us.
"In Wellington we conceded a last second try then conceded a draw. We had some good possessions against them. There's a lot of stuff in there we've been doing ok against them but certainly we need to lift and they'll be feeling confident. They think they've got a formula and we've got to prove we've learnt some lessons too.
"Clearly they're a team that believe in what they're doing and it's kind of what you would expect from a top country coming to a World Cup.
"In the last two years they've prepared well but I would like to think so have we," he said.
Beating them would mean making smart decisions, respecting what the South Africans were trying to do but being ready and knowing the All Blacks' decision-making abilities were where they needed to be.
Foster said they watched the weather forecasts but they had known all along it could be very, very wet during the World Cup or it could be hot and sticky and in both instances the ball would still be slippery.
"We're preparing for it but not banking everything on that," he said.
Replacement loose forward Shannon Frizell had joined the side with no travel issues and was excited to be in Japan.
"He'll have a little bit to learn in the next few days but he was with us and it is part of the beauty of having a bigger group through the Rugby Championship and he started against South Africa in Wellington so he's got pretty good knowledge," he said.
Foster said in comparison to some other countries who had spent large in their preparations for the tournament the All Blacks were happy with what they had done.
They had a competitive Rugby Championship, they had exposed 41 players to Test rugby and what they were trying to do, they had narrowed that group down. They had a brief break and a great hit-out in Hamilton against Tonga and they had enjoyed a fantastic first week in Japan.
"We think having that extra week in the heat has got us in great stead and all the plans and all the signs that have led up to now – all it has done is got everyone ready for the starting lines and we feel pretty good about where we're at," he said.