what are the options? keep core alive no matter the outcome?
There are certainly Two options only as mentioned by You, each have their Own Advantages and Disadvantages.
XT: 1.Wants Block size to be increased to 8 MB.
2.Wants users to switch to Centralized node which will be run only by groups of People.
Outcomes:
1.As the the Block size will increase there will be more Transactions per second.
2. All the powers will remain in hands of few Miners and it thus effect the spirit of Bitcoin , i.e, Decentralization.
3.. Some Tor related Issues are also there as each scheduled time all IPs will be stored to mark spam transactions and as a result it will affect the anonymity of people for which bitcoin is Famous.
As seen from Present scenario if Some node runners accept Bitcoin XT then it will be fine else there will be Two of them with different Peotocols and there may be situation that a transaction may be confirmed by one of them but it wont appear on the other as other has not accepted that.
In short: Every thing gonna be messy.