I think a lot depends on how well the Kingdom of France manages its debt. However, I think it is highly likely to come to war with the Dutch at some point in the future, and would likely win on ground at least.
You mean France defeating the Netherlands? Possible. That happened a lot during the 17th and 18th century. But without an American revolution, or a failed revolution, Dutch internal politicals will be very different. The patriot movement was inspired by the American revolution after all. Also any war revolutionary France starts against the Netherlands will be very different than OTL revolutionairy wars and could be defeated by an alliance of European states, the Netherlands might not fall, like it did not during the other wars with France or could even not get involved, like it wasn't involved in the 7 year war. It could even be possible for the Netherlands continuing the fight from the colonies (kind of like during WWII). All reasons Britain won't be able to snatch away the Cape colony from an occupied Netherlands and that is ignoring that during the time of the Batavian Republic (the Dutch vasal of France) the cape colony remained Dutch and Britain even returned it after occupation.
Unless you mean a Anglo-Dutch war. That is possible too, though unlikely. During the 4th Anglo-Dutch war (a stupid misscalculation from naive Dutch idealists), the Dutch were defeated, without hope of winning. Assuming the OTL 4th Anglo-Dutch war is butterflied away (likely as it was the direct result of the American revolution), it is possible another could happen for a related reason. I do consider it unlikely, as the Anglo-Dutch rivalry was basicly over in the late 18th century as it was clear the Dutch had lost. Still assuming a war happens, it will be more or less like OTL Anglo-Dutch 4th war. The Dutch lose bigtime and won't be stupid enough to try again. The peace will probably look the same. OTL the Netherlands lost 1, and I repeat it, only one outpost in India, although they lost big. So I expect a similair peace will be made. At worst the Netherlands loses more Indian outposts and maybe Ceylon. The Cape colony will not be a target. Instead of occupying a colony full of Dutchman, who do not wish to be English, it will be far easier for the English to start a new colony next to the Dutch colony in Natal. So in my opinion the most likely occurence is a Dutch Cape colony.
Of course, during this period, the British military and that of the EIC were fairly separate, so I'm not sure how much they could have a joint "focus". Or are you meaning in peace negotiations afterwards?
I am not sure what you mean. What I meant to say was that Guyana was Dutch, so would most likely remain Dutch. Even if an Anglo-Dutch war occurs, the peace treaty will focus on Dutch consessions in India, not in the America's. So even in that case Guyana (including British Guyana and Surinam) will remain Dutch.