AdVenture Capitalist Max Option

One thing I've always wanted to know, especially as I spend ages buying things in 10's, is does the Max option give you all bonuses? By this I mean do you get all speed and profit increases that you would get if you reached each one independently?

Short version: Yes, you will get all the unlocks with "Buy Max" as you would with purchasing everything individually

Long version: The individual unlocks are applied when the amount of purchases you have is equal or higher than the unlock requires. You don't actually need to purchase the, for example, 1000th lemonade stand to get the bonus from reaching 1000 lemonade stands, all you have to do is have 1000 or more lemonade stands.
Buy Max allows you to get all the bonuses same as you'd get them by purchasing everything one by one, except you can get as many unlocks as you can afford with just one click, instead of having to go through them individually.

Yes, the Max Option will do the same as buying each one individually, just a whole lot quicker.

The max option is simply there to provide a means to the user to not have to click so many times. It would be harsh for the developer to punish the user for using a convenience functionality.