If multiple Digimon with the [D-Brigade] trait are played at the same time. Does all of them gain <Rush>?
Yes, all of them gain <Rush>.
[https://cdn.discordapp.com/attachments/930985633109934090/1010168493154504745/Screenshot_20220819-074847_Gmail.jpg Carddass Email English 19/08/2022: Sealsdramon <Rush> targets]
If a Digimon with [D-Brigade] trait and a Digimon without [D-Brigade] trait are played by the same effect. Do both Digimon gain <Rush>?
No, only the Digimon with [D-Brigade] trait will gain <Rush>.
[https://cdn.discordapp.com/attachments/1011300960494157906/1073522564527292466/Screenshot_20230210-093436632_1.jpg Carddass Email English 10/02/2023: Sealsdramon <Rush> target non-D Brigade]