1: Intensive tempo would not be a good technique tool IMO because it’s too slow to get fully up into a good running position, is too long to give adequate opportunities for correction and is executed in a state of incomplete recovery (see GPP download for technique work in the early stages)
2: See point 1.
3: As you point out, these are done on the track so you have extended the volume of track work in the year, magnifying the chances for lower leg stress injuries as the indoor period goes on.