Steelfish is not cool with people deliberately calling cops to his bar. Which is probably why he pays them not to show-up unless HE calls them and to report calls involving him. Just good business for a fixer with a rep for hosting neutral ground. He doesn't really care if people murder each other OUTside as long as it can't be said they violated his hospitality.
Richter is totally willing to kill Diego at this point but that's irrelevant; he's wiling to kill everybody except maybe Jimmy, who he's starting to like. Because he's kind of, well,
insane] to the tune of "keeps his 'wires running whenever he's not asleep". So certainly don't go by what he's doing

.
You can write him out and make a new character if you really want to. Or you can keep going with him, as the rest of the group seems to be willing to let it slide. Entirely up to you.
Also, pretty sure the low essence thing applies to ALL healing-category spells not just Heal, so it's harder to buff low essence chars as well.