Hello. I am currently using cubase 6. My projects are all set to 44.1kHz 24bit. I’m about to export some final mixes. If I export at 88.2kHz, will all live plugins render at the higher sample rate?
Any thoughts on this subject? Thanks 
All Online Processing (live plugins etc) is executed in the 32-bit floating point no matter your sample rate.
As for your question:
Most plugins do some upsampling internally, no matter your project sample rate. So IMO, you will gain nothing.
Besides that, what format is the end format? If that’s 44.1, stay there, is my advice.
End format will be CD and vinyl. It would be nice to have a higher quality master for vinyl… Also dithering down to 44.1 from 88.1 during mastering should retain some of the quality…
Surely if the plugins have the ability to run at higher sample rates, when you export at 88.1, the plugins should render at 88.1??
Generally you dither down at bitdepth reduction, not samplerate reduction,
The plugins render at their internal samplerate, then output to the Cubase project samplerate.
Exporting at a higher samplerate will process the whole project at the lower project samplerate, and then upsample the lower samplerate´s mixdown. If you want to retain the “quality” start with the higher samplerates for the complete project and expecially the single files.
That would be the best approach indeed. But, to get a better intermediate quality the OP could export audio from Cubase in the higher bit rate, so 32 bit float - leaving sample rate at 44.1k. Increasing sample rate to 88.2k will only double the file size and adds no quality. When going to delivery format, use dither once for CD (down to 16 bits) and once again for the vinyl delivery to 24 bit.