Are there any equivalent or similar prefixes or nicknames for 阿 or 小 (added in front of a name in Chinese) in English?
I don't think there is a universal prefix equivalent to 小 or 阿. Certainly you can add 'Little', but that's not a prefix, but an adjective.
In the West, nicknames follow different patterns, mainly using the first syllable of the full name and adding an
[i] (-ie, -y or similar):
E.g. John --> Johnnie, Andrew ---> Andy, Lisa ---> Lizzy, etc.
Other countries have similar fashions, adding -(e)tte [French], -chen, -le [German, with some regional differences], -ito,-ita [Spanish] -ka, -ška, -čka, -ek, (Czech and other Slavic with different spellings).
Some nicknames are completely different from the formal given name, e.g. Richard --> Dick.