What this "a warm lot" means in this case?

Solution 1:

OED's entry for warm (paywalled link) is, fortunately, suitably antique since it was first published in 1921 and doesn't appear to have been updated much.

However, more context would help:

...Mr. Woodley by name, who was always there. We had got as far as this, when who should walk in but the gentleman himself, who had been drinking his beer in the tap-room and had heard the whole conversation. Who was I? What did I want? What did I mean by asking questions? He had a fine flow of language, and his adjectives were very vigorous.

OED has

2.b. b. Of persons: Glowing with exertion or exercise, with eating and drinking, etc.; often with mixture of one of the senses A. 10 – A. 12.

10.a. Of persons, party-feeling, controversy, etc.: Ardent, zealous, keen; eager, excited, heated.
      b. Of the passions or disposition in general: Prone to excitement, ardent, impulsive; apt to disregard the voice of cool reason.
11. Hot-tempered, angry.
12.a. Of the heart, feelings, etc.: Full of love, gratitude, approbation, etc.; very cordial or tender.

I don't think 12 is relevant, but warm meaning outspoken, boisterous or hot-tempered from imbibing is not improbable.

Thus, of your list, it's (3), with this meaning for warm.