Q3 Answer
The agreement is signed with the Institute. You may have few Institutes from the same country. The budget line, remember is quite tight, only 100.000 EUR for all the Domains and +/-200 Actions. The request shall be done at the 2nd year budget grant, to be negotiated with the SO, upon the funds are available. The scientists from ST Petersburg could attend your meetings, but should fund their participation with their own funds, in case they are officially approved by COST as part of the Action as NON COST Institution. You can invite them exceptionally as experts funded by the Action budget.

EU scientists, coming from the COST countries members of the Action can go to STSM in Russia. The missions have to be funded by the Action budget.