In global option there is preloading options.
You can reduce the preloading time or try turning some of the preloading options off.
http://www.ufe3d.com/doku.php/global:preload

A lot of objects can potentially be instantiated with preloading so that might cause a bottleneck of some kind.

You may run into a small stutter when first creating objects in a match without preloading first.
It would be a lot of work to change UFE to a pooling system.

Instead of changing any UFE scripts, I create my pooling systems to work with UFE.
You could try a custom preloading script
You could create a script called preload, simply pool the objects you want then call unity's warm all shaders.
we could have a method in the script that first enables the gameobjects then calls warm all shaders then disables the gameobjects.