As for the pronunciation of 'bst' in 'abstulit' is it 'abstulit', 'apstulit'?
Is it 'absum' as it is written or 'apsum'?
I know 'urbs' is 'urps', obtineo' is 'optineo', 'obtempero' is 'optempero' etc..
I believe it's apstulit and apsum. The consonant combination bs isn't really pronounceable. It must turn into either ps or bz. In Latin, it was ps. We have alternative spellings like apstulit as evidence.