Can I make a sweet hot water crust pastry?
You can easily add sugar to pie crust dough. In Germany, the formula "3-2-1" doesn't mean "flour-fat-water", it means "flour-fat-sugar". And I believe that I have seen shortbread cookies with even higher sugar ratios. To clarify, you are supposed to use sifted confectioner's sugar, since any larger crystals will have a hard time dissolving. 

These doughs are generally made as shortbread (= simple mixing), not as a pate brisee (which is hot water). But I think the French do make sweet pate brisee. Couldn't find a source though, since it seems modern French websites don't care much for the traditional distinction of pate sablee (cold method) and pate brisee (hot water method). Still, I would just go ahead and try it - mix the confectioner's sugar into the dough and see how it works out. 

Also, I wouldn't substitute the lard. I love the texture it gives, and I am personally not at all put off by its taste in sweet recipes. I know some people may react to it as weird, simply because they have never encountered the combination, but if you give it a chance, you may be pleasantly surprised.