Howdy. So just throwing this out into the wind, as I'm curious.   But with all the varients, while most don't seem to touch subclasses in specific. something I think would be neat-if they do that, would be to offer up the old Alchemist Bag from the previous UA Version of the Alchemist.  Just updated to better fall in line with the rules and other abilities.
Label the varient replacement Combat Chemist

I personally would exchange that for my Elixirs.  It wouldn't require restructering any of the other ones-as none of the other features really connect to Elixir except the temporary HP. Which. would fit the old Elixir of healing from the Alchemist Bag (which is a scaling 1 application per person per long rest potion/elixir).  So at level 9 once a day they could imbibe a healing elixir doing the scaled healing + small amount of temporary HP.  Which is would be a nice way of extending their Healing ability, while also letting them use their spell slots to support in other ways.

Just a few tweaks to the old version--making them act as the actual Alchemical Weapons, giving profiency with attacks on them. Changing them from Save or Nothing to Attack rolls for the Acid/Alch fire,-upgrading in damage as per original, keeping the Tanglefoot as a Save vs restrained, thunderstone as a save.  Add in Liquid Caltrops-which creates either straight up caltrops-which expands in area as the ability upgrades over time.
Include a line in it that these items count as Alchemist Tools for the 5th level ability, and are modified by that ability (so youget INT to damage/healing on them). 
Make the item creation a Bonus action--not a specific "create and throw"action.  That way it interacts easily and readily with the normal Action Economy rules.  And it gives the Alchemist Subclass its own Bonus Action-which it thoroughly lacks.   As a bonus action they could effectively use it to make a temporary item to count as Alchemist Tools to gain the +INT to spells, without dealing with the issue of having Tools in your hand, in combat.

This varient loses its ability to buff allies via elixirs --but it gains its own form of debuffs, and attack "cantrip" style abilities that scale. Which frees up their cantrips and gives them a unique method of combat.   (andstill has spell slots for normal spell bufgfs)

So its outside the norm. But other alchemists, if it came up would you eyeball that kind of variant for use?  I feel like it would give me a solid method of play, which in term would allow me to choose all support cantrips and support spells, and give me more variety-while avoiding the current awkwardness of action economy to make-handoff and consume an elixir in battle (though generally you would be handing them off prior to battle anyway--but the 1d4 one is rather strong and may warrent handing out in an ambush or other awkward moment).

But for me this would feel more alchemsit like, while I fluff my abilities, and much of my infusions to be Alchemy based.  This would actually be just about my ideal charactetr class. So I am very biased