Are there any more requirements? In terms of CPU capability, traffic or harddisk?
And are there any specific regions that the server should be in? I mean if someone does US I could do Europe and/or Asia.
No, not really, the only hard requirement is RAM. SSDs and powerful cores make synching and indexing faster, but you'll get there with spinning disks and slow CPUs as well but you can't do it with 512MB RAM.
Also the server location doesn't matter at all. If people can reach the BE to check a transaction they will certainly not care if it is in Africa, Alabama, Albania or Anywhere.
Since SFC has 4min block spacing, there are only ~133'250 blocks now, that further reduces the requirements for a block explorer, other coins have already several mio blocks and that takes a lot of time and ressources to run a BE for.
And may I ask how you are involved with the project?
I am not more involved than you or most of the readers in this thread: occasional miner and hodler of SFC.
I am currently running block explorers for 3 projects I support, but I am running out of ressources and need more servers before I can expand on that so I am only offering to help but not to run it myself.