The beauty of Delphi is that if you design things properly you don't have to settle.
Start easy with DMVC, which also has demos for Bootstrap to get you started and make sure that your data classes are well separated by the DMVC code.
Once you have that running, you can really look into alternatives. The only issue would be the events: for that, I would go with push notifications (for example, Kinvey) on all platforms.
The reason for this is that you're still going to need them on mobile, so you may just as well use them across the board.
Then again, plan it properly and you can change things around a fair bit.