As it happens, all of the issues that the SAB brings up in Mark 11 were addressed when I covered Matthew 21 (which also covers the parable of the vineyard at the beginning of the next chapter).
So Mark 12 ends up likewise being very similar to Matthew 22, but there are a few differences there. Verse 26 asks "Who appeared to Moses in the burning bush?" I'm surprised I didn't cover this back in Exodus 3; I assume this is a note that has been added since I covered Exodus. Anyway, the O.T. passages that talk about this occurrence make reference to "the angel of the LORD", and thus the SAB says that it was an angel, and not God. However, most people who study the Bible understand that "the angel of the LORD" is the equivalent of God, so while it may sound strange, it's not a contradiction.
I addressed how many gods there are in Exodus 12. The question of "When was the Holy Ghost given?" is a tricky one that I thought I'd addressed, but it appears not. It gets more complicated than even the linked page lets on, as I think you can rightfully include any mentions of "the spirit of the LORD" which are plentiful in the O.T. Anyway, the answer is that the Holy Ghost was given generally to the Church as a whole at Pentecost shortly after Jesus' resurrection, but there were occasional dispensations that preceded that event.
Those are all the big issues from these two chapters, but I'll make a comment on the SAB's final note on 12:41-44, "Jesus believed in progressive taxation." I'm happy to think that this may have been the case, as I myself am a fan of progressive taxation, but I think reading that into the scene may be a bit much. In fact, given that the widow "cast in all that she had" progressive taxation would imply that Jesus thinks everyone should be taxed at 100%.