What items can a Thief use as a bonus action with his Fast Hands?

Question

At 3rd level, the Thief archetype for rogues grants a feature called Fast Hands that allows:

[...] the bonus action granted by your Cunning Action to make a Dexterity (Sleight of Hand) check, use your thieves' tools to disarm a trap or open a lock, or take the Use an Object action.

Player's Handbook p. 97

The following items all require the use of an action in their descriptions:

• Acid
• Alchemist's Fire
• Ball Bearings
• Caltrops
• Climber's Kit
• Healer's Kit
• Holy Water
• Hunting Trap
• Lantern, Hooded
• Oil
• Poison, Basic
• Potion of Healing
• Tinderbox

Magic items are called out specifically as being incompatible with the Fast Hands feature:

If an item requires an action to activate, that action isn't a function of the Use an Object action, so a feature such as the rogue's Fast Hands can't be used to activate the item.

Dungeon Master's Guide p. 141

And potions are magic items, as indicated by the italic text in the Player's Handbook and their position in the Dungeon Master's Guide's magic item treasure section.

So can all nonmagical items that require an action for use be used, or do items that require an attack roll (acid, alchemist's fire, holy water, etc.) not qualify?

Answer 1

The description of the Use an Object action says:

When an object requires your action for its use, you take the Use an Object action.

So any nonmagical item that specifically requires an action can be used with the Use an Object action. More specifically, everything on your list, with the exception of potions as you noted, can be used with the Use an Object action.

Answer 2

You use the Use an Object action to, as you say use an object.

To make an attack you must use the Attack action or some other feature that allows you to make an attack.

You can use "acid, alchemist's fire, holy water, etc." with Fast Hands provided that you do not attack with them; for example, you could pour them out on the floor, toss the flask to a companion, retrieve/stow the item, however, to hurl them at an opponent you are making an attack and Use an Item does not allow this and, by extension, neither does Fast Hands.