1. I will likely stick to using my coins on current chain. I expect that my wallet of choice (Electrum) will allow me to do this.
Yes, Electrum will allow you to choose the chain that you want to use. You can do this by choosing the Electrum server which you connect to.
3. I will end up using one wallet with coins on new chain and another with coins on original chain.
Yes. You will need two separate wallets and instances of your wallet software.
4. I do not feel I am technically competent enough to download the entire chain to tweak with or run a full node (and as am still a casual user, have no desire to be).
Running a full node is extremely simple; just download, install, and run Bitcoin Core.
Are my assumptions safe enough?
Yes.
Splitting the coins will be a bit complicated. If such a bad split actually happens, someone (maybe me) will write a detailed guide on how to do it.
I will be writing up detailed instructions for that and either adding it to the Bitcoin.org alert or making a post here with those instructions. I have written the basic idea of the tainting method here:
https://bitcointalk.org/index.php?topic=2012799.msg20104865#msg20104865. This method is also automatically done by Bitcoin Core since it will include a locktime of the most recent block when a transaction is created (with some randomness that allows for a locktime to be chosen that is up to 100 block behind). So long as the minority fork is more than 100 blocks behind and the transaction pays a high enough transaction fee, then this method with locktimes will work.