How to drill into cinder blocks and attack brackets

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).

Those "big wooden casts" are called "forms", by the way. Very often brick is chosen over concrete for its aesthetic value. It's also relatively easy to double-wall brick for insulation purposes, but it's extremely difficult to pour two good-quality 4"-thick concrete walls immediately adjacent to each other.