As long as the war is not officially declared, Germany can sell weapons. Afterall, they sell plenty to the US, UK and those guys never stopped bombing countries in the mid east.
No, can't.
West (NATO, EU) have imposed sanctions on Russia. From the 2014 they don't sells military and dual purpose equipments to the Russia.
What about the engines:
The two Chinese TBD620V12 (Made by the Henan Diesel Engine Industry Co., Ltd (HND), part of the "Сhina Shipbuilding Industry Corporation" - CSIC) diesel engines have break during the first trial.
In addition, the Chinese engine has a much higher fuel consumption compared to the German MTU 16V4000M90.