What are potential British and French wartime objectives against Spain, and the Austrian Habsburgs?
In North America – Britain gaining the Floridas
France gaining Texas to the Rio Grande (or, more ambitiously, Texas, New Mexico and Alta California)
Potential other areas of interest – La Plata? Uruguay? Venezuela?
In Caribbean, Puerto Rico for Britain, eastern Santo-Domingo for France?
Philippines to France, or Britain, or split
In the Med, Mallorca or Ibiza?
Possibly Sicily or Naples for France, with the other for Britain-
Possibly Milan for France, maybe with a British Sicily - some of this all would be at Austrian and not Spanish expense.
Against Austria – claiming Austrian Netherlands for France would be too contentious most likely. Milan might be a little more tolerable
Ottomans would probably like the Franco-British coalition and join it to recover territory from Austria
Dutch most likely neutral. If they went against Anglo-French, they would just be a victim, losing Caribbean and African and Indian colonies to Britain and France. If they went anti Austro-Spanish, they have potential to gain some very small Spanish islands, part of the Philippines perhaps, Santa Margarita island, at very topmost, Puerto Rico, but nothing bigger at Spain’s expense. Probably would not want to acquire Austrian Netherlands, even if it is on offer potentially.
Possibly the Dutch could take Ostend Company ships, money and factories in Indian Ocean as booty.
Prussians – Silesia? Are they strong enough? Or if the Prussians switch to pro-imperial side, they go for Hanover, or Dutch borderlands? Or compensation at Polish expense. Hanover or Saxony could be targets, although complete liquidation would be difficult, and it is basically hard to see the Austro-Spanish side win.
In OTL, the French were side-switchers.
Knock on effects for later wars –
Prolonged Anglo-French peace means colonies stay loyal or can be put down and do not have prospect of sufficient help.
But, presuming they turn on each other, Britain could end up with all of French North America.
Other compromises could include, an Anglo-French transcontinental boundary leaving Britain with Ohio country and French with Canada.