Answer by Daniele Santi for tftp vs tftp-hpa

Well, the tftpd-hpa description says:

tftp-hpa is an enhanced version of the BSD TFTP client and server. It possesses a number of bugfixes and enhancements over the original.

So you should certainly choose the -hpa version, unless you are required to use the BSD version for some reason (which doesn't seem your case).
BTW, you can also check the atftpd package.