Your sentences sound quite queer due to your construction:
The amount of people who surrounded him was xy.
At first I read the sentence as
The amount of people who surrounded him was xy.
and was expecting a which instead of the who. That is of course my problem, but why not use a sentence like
Only a few people surrounded him. (while his fellow had by comparison gathered a rather large crowd) **
There is another aspect to your question also.
- few people
- a little amount
Using few with amount should not be correct, since amount is singular while few must be used with a plural.
The adjective is referring to the subject - amount, so only
The amount of people who surrounded him was little.
can be correct, even if one would prefer another construction.
** While I was writing my answer John Lawler commented and R Sahu posted similar sentences.