> 2. How can старше be used for "not necessarily old ones"? As in young ones?! Contradictory?

Also as in being hierarchically senior, `старше по званию`

> **Младший** - **youngest**

Not sure if it's correct. `Youngest` is rather`самый младший/самый молодой`, whereas `младший` is simply `younger`.

Otherwise the sentence `у меня два младших брата` wouldn't make sense as it would say `i have two youngest brothers` 

> 3. Can моло**ж**е be used in all contexts, therefore negating the need to use младше?

Indeed both `младше` and `моложе` are being used with inanimate objects, although `младше` seems more frequent, but i personally still feel uneasy about this usage. I guess it's more pertinent to scientese and professional lexis than to general purpose language.

It's almost as using the English `younger` with inanimate objects.

If i had to choose a more fitting word i'd opt for `новее/более новый` - `newer`