Very good points.That is not true I remember seeing TEL inside silo it is big enough all right. The TEL cabin is designed for 2 compartment allowing the rocket head to sit between them so it is low profile. What do you mean by shifting to other region because The UGW is all over China it is not limited to specific region or mountain. It is mostly in central Chinese mountainous area but some of them in the north, west, east and south all over the country. I think the silo complement those UGW basing as they allow speedier deployment specially if it solid rocket like DF 41 and can be launched on warning.
However, Can UGW accommodate the bigger TELs and missiles. From the videos of UGW, I think it's a bit congested.
What I've understood -
The silos would be in Western China (to take the artic routes)? So the UGW would be in Central Eastern Mountainous region.