Can I run Elecrtum and Electrum-ltc on the same machine? Note that I'm running Xubuntu. Thanks in advance.
Should be fine. You can even run the same coin side by side as long as you configure the ports differently. That is for normal use and things like mining and in depth coin work might not work right. But, if those work like other coins, and they do not argue about ports, then they should be fine and not argue at all. The Java might be an issue, as those are based on Java, but if it is important, you could even unzip the library and fix clashes based on things like variable names and such.
The OP was asking questions about electrum and electrum-ltc, not about core. Electrum is an SPV wallet, not a full node implementation, it doesn't listen to ports on your local machine, hence you do not have to configure ports differently.
Since electrum is not a full node implementation, it does not receive unconfirmed transactions, nor does it verify new blocks... This also results in the fact you cannot request a block template from an electrum wallet, so you can not use it to mine (sure, you can use an address generated by electrum to fund as coinbase transaction, but that's about it, it is not a mining node in any sense of the word).
Also, electrum is written in python, not in java