Well you could submit patches to wraiti's pathfinder branch on github. https://github.com/wraitii/0ad/commits/pathfinding I'm interested of the slowdown you have when using the interface, could you be more specific ? And maybe create a ticket patch for it ?
The Pathfinder still needs to be rewritten. It's called only when moving units. So if you do nothing it won't lag About the Unit List, what version are you on ?
Problem is who except english speaking dev will be able to help I think the only dev that spoke russion is fcxsanya and he/she is retired. Best thing you can do is write in both language. If we don ´t understand we wiĺ have the source message in russian. do you have any other ideas ?
This has been discussed in a lot of threads. I think the aim is to keep things in english so everyone can participate and ideas are not spread and lost. Therefore the solution was try to speak english if you can ´t write te traduction next to it and hope someone on the forums or in the team speak both your languages.