Is it possible to remain on DT1 when you're just sitting around quietly? And also would it be possibe to be on DT2 even if you're removed from DT1?...
If more than 100 users are eligible for DT1, it's not guaranteed you'll always be in DT1, but unless the numbers of eligible users increase significantly, you should be in DT1 most of the time as long as you fulfill the eligibility criteria.
And also would it be possibe to be on DT2 even if you're removed from DT1?...
Yes, it's possible.