Almost all SDR's are direct conversion (although direct sampling is starting to become popular now that reasonably priced high speed ADC's are becoming available).
True, although the cheaper ones have a pretty significant spike at DC and you end up using a tuning offset and IF in software instead. Not the case across the board, but pretty common.
The significant spike at DC is an inherent issue with Direct conversion receivers, driven by circuit level DC offsets and IP2 contributions. Offset tuning works, but you're stuck with sucky image rejection (30 to 40 dB at best)