Walls – Minimum length of concrete fasteners to floor and ceiling to attach a wall

My vote is for option 3. I've never seen angled pipe flanges either, but you could make a couple for this purpose out of 1-ft lengths of pressure-treated 2x6 with a pipe-sized 45-degree hole drilled in each. Then anchor those to the walls vertically. That would give you the added advantage of spreading your anchors out a bit in the cinderblock, rather than having 3 or 4 smallish anchors on a 2" radius or whatever.

I don't like option 1 just because you probably don't accurately know the strength of the concrete ceiling either locally or across its span, and that option's failure mode could be disastrous. Not to mention the likelihood (as you mentioned) of hitting steel and needing to rent a core drill and use it upside down on the ceiling. Not fun at all.

My main concern with option 2 is the tension load the bracket anchors are going to see. These blocks are very strong in compression (and by extension any anchors used in them are strong in shear), but not strong at all in tension (and by extension anchors don't resist pullout forces).

easy solution that we use all the time. get yourself a powder actuated gun (you will have a much easier time if you get a strip load gun instead of a single load gun). use 3" pins and red loads. just make sure when you pull the trigger, you have a good amount of force on the gun (so it can't kick back at you). this should set your 3" pins almost flush. if your concrete is super hard (for whatever reason), just hit it a second time with the gun. its seems dangerous, but we have put probably 10,000 loads through each one of our guns, 10% are probably second hits. no problem. if you would like a tip - strap the furring afterwards with 3/4 ply ripped at 3", with shims between the furring and the strapping. this will give you a perfectly flat wall with wider attachement points for all the drywall. much easier to make the joints line up in the drywall.