Is it bidah to set specific amounts of dhikr per day, for example I want to say a minimum of أستغفر الله x1000 and سبحان الله x400 a day? Also is a digit tasbhih counter considered bidah?

Better to start away from the tasbeeh counters and do tasbeeh with your fingers cuz they will speak on the Day of judgement. As for making certain numbers and u don't believe this is a sunnah that's not a problem if u decide today u kake 100 istighfar tomorrow 200, that is alright.