Hello 布隆伯格, -later is already the comparative of the adjective "late ",so it is rather late , later ( comparative), latest ( superlative) - next is rather the superlative of the adjective "nigh" nigh, nigher ( comparative), nighest or next ( superlative) ( old form) near , nearer ( comparative) , nearest or next ( superlative) - southern I am not sure about that one ,but the superlative might be "southernmost" ,maybe others could elaborate here . :)

It can't have a degree Mike, if it is a "noun" or an "adverb". But it can have one if it is an "adjective" and in that case it is the superlative degree of vicinity . His house is near to the supermarket, hers is nearer and mine is next to it . It means mine is the nearest to the supermarket .

But word “next” cannot have any degree