Barnaul was not a village. It was a major center for trade and culture. Population before Revolution in 1917 was at 70,000. It was modeled after St. Petersburg, until there was a major fire destroying many parts of the town.
The majority of the Germans who settled in the Altai area were Mennonites from the Molotschna and Choritza areas of the Black Sea region (Yekaterinoslav).
Did the family have some marital connection to the Mennonite Community?
Mennonites did/do have Swiss German roots.
There were Resettlement Contracts signed w/Resettlement Bureau in Barnaul. For all intents and purposes these were applications for homestead property.
This area was also known to have been a hideaway region for "Old Believers".