I doubt the OpenVPN changes are contributing to the issue you are having. The NTPD issue is probably due to the router not having WAN access since the authentication step hasn't been performed.
Several releases back, some ntpd issues were resolved by setting the item below to "No"
Tools -> Other Settings ->
Wan: Use local caching DNS server as system resolver (default: No)
I use a GLiNet travel router when staying at hotels and always have issues with the splash screens. The OpenWRT firmware on my travel router has a repeater mode. I usually have to connect to the hotel wifi first and note the IP address of the splash page. After I connect a device to the travel router, I then go a browser and enter the IP address of the splash page and authenticate. After that, all devices that connect to the travel router can then logon.