No. Even if you hide your UI, it will persist.
No. 20 seconds or if you lose your shield due to taking damage, whichever comes first.
As of this writing, there are no news on increasing the number of knowledge transfers with the release of Machinist. Currently in KR, knowledge transfers are 12, we have 9. Purchase a Vern powerpass and knowledge transfer the rest, or purchase a Punika powerpass.