Good question about beef (or poultry) liver. Since it is very bloody, salting alone is usually not sufficient. In this case, the liver must be broiled to drain out all the blood so that it is considered kosher for consumption.
Small amounts of blood, any blood whatsoever, must be avoided. My childhood Orthodox rabbi once said that when he ate roast beef in a deli or restaurant, he would always order it well-done, even though the restaurant was kosher to begin with. There is in Judaism kosher and glatt kosher. The latter may be translated strictly kosher, since it means that particular care is taken to drain ALL the blood from meat. In addition, certain nicks in the lung of a chicken, for example, would render it non-kosher according to glatt kosher standards even though it might still be considered kosher. It all depends on how orthodox one is: there are small differences even among Orthodox Jews regarding what they will eat and not eat, as well as other commandments.
Insofar as Conservative Jews are concerned, it also depends on how “orthodox” they are with regard to kosher dietary regulations; in other words, they too vary. There are official Conservative guidelines but Jews being what they are do not always lead their lives according to them. Still, you are much more likely to see a relaxing of the kosher rules among Conservative Jews than Orthodox Jews. Reform Jews are even less attentive to kosher regulations, but even here, it depends on the individual Jew. They may just avoid pork and seafood, and observe nothing else regarding kosher, or they may be more observant. Among Jews, it is certainly the case that one size does not fit all.