SparkyTD:
My problem is, that the remote's datasheet says that it operates at 868,35 MHz, but in most online stores I could only find 868 MHz transceivers. Can I assume that it's a standard value and they will be compatible with each other? Does that 0.35 MHz matter?
868Mhz is a standard band, but only where you are allowed to use it.
What frequencies you can use, without needing a specific licence, varies between regions and countries.
Even within the 868Mhz band, if permitted in your country, there can be differences in the exact frequencies, powers and duty cycles you are permitted to use.
Whilst it would be nice if there was a universal 'standard' frequency, unfortunatly there is not.
You will also find that different tranceivers are not directly compatible with each, they often use completly different software for instance.