The Singapore government would put the kibosh on any lawsuits to avoid causing problems with the West. Even the Chinese would likely do so also, as trade with Europe is worth far more than anything with Russia, and China already basically dictating the terms of that trade to Moscow already.
Hong Kong is more the issue than Singapore, but in both cases the matter would go to court. The branches are part of the total. Assets in Brussels must get shipped to HongKong if the lawsuit loses.
In fact, since it is all electronic, it would be instantaneous. And Euroclear values its business prospects in Asia.
It’s very much like what happened in Cyprus during the Greek crisis. Russian assets at Cypriot branches of British banks were at risk, but they were branches. When Cyprus announced on Friday afternoon that there would be a bail-in of the banks (funded by depositors) on Monday morning, Russian business people moved their assets from the Cypriot branches to the London branches, and then back to Moscow on Tuesday.
They had been the targets, but their money escaped.
It was this single event that started the ball rolling towards Bitcoin’s international aspect. Government confiscation is not possible in the blockchain.