I thought about your question and here is the answer I came up with:
With the data available, I do not think anyone can reliably predict anything, here is why:
There is absolutely no guarantee, that those people will have even closely the same ratio as you listed. K/D ratio depends on a lots and lots of factors and even if it were simpler, a mean value alone is next to useless when you try to make any meaningful predictions in statistics.
It is however even worse, because even if we assume, that those players will have the same ratio as listed, we still can't decide who will win, simply because it depends on how many frags players have. If the guy with the worst ratio has the most frags, your team is pretty much screwed.
To see what I mean, let's take a look at this very simple example:
Imagine a game where a team need 34 kills to win. There are two teams:
Team 1: Tom , Jerry , Spike
Team 2: Garfield , Odie . Jon
Here is what happens in the first match:
Tom kills Garfield 8 times , Jerry kills Odie 8 times , Spike kills Jon 4 times
Garfield kills Tom 16 times , Odie kills Jerry 16 times , Jon kills Spike 2 times
In this example the team 2 wins.
Now let's take a look at a second match:
Tom kills Garfield 2 times , Jerry kills Odie 2 times , Spike kills Jon 30 times
Garfield kills Tom 4 times , Odie kills Jerry 4 times , Jon kills Spike 15 times.
In this second match, it's the team 1, that wins.
In both cases the ratios are:
Tom 0.5 Jerry 0.5 Spike 2
Garfield 2 Odie 2 Jon 0.5
You have the same ratios and yet the outcome is different.
Of course that kind of hypothetical match most likely never happened: I just made it up to show how complicated things can get and why the ratio is clearly not enough to predict the outcome of a match.