You can use buckwheat for pizza dough, but it will not be anything like an actual wheat flour. Buckwheat isn't actually a grain and doesn't contain gluten. The gluten is what gives pizza dough it's chewy texture (and makes it stretchable when you're tossing the pie).
You need to substitute something like xanthum gum to make up for it. If you want to go down this path, google 'gluten free baking' for advice and directions.
On the other hand, buckwheat makes an excellent partial flour substitute in pancakes.
Flour labeled as Cake flour usually is weak flour: low W value, or less formally "low protein" or "fewer gluten". This is somehow weird, as some cakes will require weak flour, whether others nedd strong flour (for yeasted dough cakes, if they add lots of fat/oil to the dough, if they add lots of sugar, pieces of fruits/nuts, etc).
I specifically don't know whether Maida is strong or weak flour, despite this answer and it's comments.
Wheat plants has been selected for several milleniums to get more productive varieties, and, yes, grains that give stronger flour.
Substitutes as weak flour
Trying to get flour from a more "primitive" variety of wheat, such as spelt, emmer or einkorn. These are expensive where I live, and usually sold as bio, but maybe spelt is easily found in India. As they have not been so "genetically selected", they still have less gluten than today's "normal" flour. They also tend to have more and better taste than "normal" flour.
Another flour with low gluten content is rye. It has a different taste than wheat, but I thing it fits really well with cakes. This grain grows better in colder climates, so I'm not very sure how hard will it be to get it where you live.
Other flours, as rice or corn / maize have no gluten. It means gas bubbles won't be trapped in, and will result in a much too dense crumb. You might search some gluten-free bread tricks to solve this.
Substitutes as strong flour
Any bread flour will probably work. Maybe it won't rise as much and you'll get a crumb with a denser consistency, more similar to a "chewing gum" than a "soft cake". But if you are ok with this, you can go on.
Note(Thank to @Anisha for the suggestion):
Notice that different flours have different absorption, so some readjustment on hydration should probably be made to the original recipe.
Best Answer
Short and sweet... Use cake / pastry flour. At 5-7 % protein vs. 11% for AP vs. 13% + for bread flour, that means a lot less gluten formation. This protein, when mixed with water and subjected to mechanical working is what produces gluten. The higher the protein percentage, the 'tougher' (due to the gluten) the final product. Always use cake or pastry flour when making any type of cake, even brownies. And a little extra egg won't hurt, either.