No to the first question.
ThomasV has stopped development of electrum-server and is encouraging all to use ElectrumX. The main advantages of ElectrumX are the smaller DB and mainly the much faster sync time if building the db from genesis block. It is literally 100+X faster.
This is interesting. Can ElectrumX be used on top of a current local blockchain (Core)? Or roughly how long will it take to sync entire blockchain up from scratch on ElectrumX (e.g relative to core)?