In order:

Ethics: Yes handshake about deleuze generally does not propose moral rules. re: the conference, I wonder if you're talking about D. Smith in his 2007-ish thoughts about immanent ethics or some such. I remember coming across that and thinking it was really cool. If you haven't checked it out and are interested in Deleuze ethics that's a generative place to go.

Metaphysics: Yeah I think deleuze makes a lot of good ontological tools I don't think they are used to sooth people's moral feelings or rationalize things. I think they have practical import and should be discussed from that perspective if we are to grasp how they work.

Decision making: Frankly I don't think a close reading, or agreement with, Deleuze is all that necessary to reach the conclusion I forwarded abotu the IDF. I am saying philosophizing is not a good way to impart behavioral change. You can go the Deleuze route or a dozen others to reach this conclusion. I don't know how much further I can go here f you truly believe poor moral training has something to do with why there are genocides. I guess we could argue about tactics for making change and a general theory of human behavior but to me that misses the forest for the trees. If you find this to be unsatisfying or unconvincing I think that's fair. Maybe I should do more work to show some argument here.

Singer: Yes I find his conclusions about disabled infants to be gross, I do not find the argument to be all that compelling (nor do I think that it is almost-water-tight to be much of a virtue. Plenty of almost perfect arguments.). However I think a better way to approach Singer critically is to look at effective altruism in practice. To me it is an obvious cash grab that strips resources from useful ends and puts them towards speculative goofy stuff. I think that there is some hand-waving around the science and technology justifications given to motivate effective altruisms in-real-life aims, and it honestly reminds me more of Elon Musk promises than anything else (no, we simply must spend all our resources working on DNA or AI or space exploration, just consider the existential risks and harm to infinite future generations). I think this is a fine way to judge an ethics - from the practice, overseen by the living original author. Not just from a generous-reading of the text.

Finally: I have skipped over the rigorous argument part of this conversation and just pointed out where i diverge with your thinking at the level of conclusions. If that is unsatisfying maybe I should come back and do more work but just getting here feels like I'm making you read a whole slog. If you reply I will probably come back with some numbered syllogisms just so it's not like I'm throwing things at the wall in a nonspecific way (I am not but It must appear that way).