As a (crappy) solvent, acetone could theoretically be used. Prefrence still goes for hydrocarbons like hexanes, a diy redneck alternative would be gasoline.
for the KMnO4 the permanganate ion is the most important, so when the compound splits into ions the potassium ion does not matter, in this reasoning barium permanganate or other earthkali could be used as the oxidizer.
as for a basing agent, ammonia is probably a good one. It is not hard nor illegal to get.
Ammonia hydroxide could be used instead, but it is more expensive.
Sulfuric acid is really a must, hydrochloric acid is not really suitable for the extraction
also acetic acid can not be used. Weak dilluted HNO3 maybe, not sure since it may
partially nitrate the cellulose in the coca leafs which may end up as contamination in the end product.
(Nitrocellulose is a vasodilator and increases BP)
For further questions my DM's are open,
Best regards