lz can read martin's "analog integrated circuit design". there is a comparator chapter. the design of latch is also discussed.
if u dont want to use cmfb. diod connected load must be implemented to stablize the DC bias. however this could decrease the gain. u could also consider to use clock as the switch signal to bias the tail at a level u want instead of using the clk directly. in this way, classic theory on opamp described in allen can be applied.
the principle of comparator is simple. actually every principle in analog design is not complex. but the design leads to high performance is always not straightforward. so take care and good luck.