I'm pretty confident that the answer is yes for each country.

France (>.95) This alliance definitely wins. Using casualties as an indirect measure of military strength, France is third most (after Germany and Russia). But this is a total counter-factual because there is essentially no historically plausible path to WWI that leads to France and Germany on the same side.

Historically, I believe the last alliance between those states before WWI was the War of Austrian Succession (and Prussia was not unified into Germany at that time).

Russia (>.75) Second most casualties, but with the benefit of hindsight, there's strong reason to think this overstates Russian military power - although Russia defeated Napoleon and would go on to defeat Hitler with minimal assistance. Still, even assuming that Russia is equivalent in military power to the second raters like Ottoman Empire and Italy (a very questionable assumption), the removal of the Eastern Front probably adds enough German troops to the Western Front to overwhelm France.

UK (>.65) Fourth most casualties. Fought on the same front as France, so removal of those troops increases leverage on the outcome of the France-Germany fight. As you may know, the French army barely made it through the war, so lack of other forces to absorb casualties seems plausible for swinging the outcome.