Based upon just looking at the diagram and given the difficulties you are having, I might consider removing the LCA from the subframe, but leave it temporarily connected to the hub/upright. I assume the goal is to move the entire hub away from the transmission enough to feed the end of the axle through the hub so you can then remove the entire axle. Then once you get the axle removed, I would remove the hub/upright from the strut and take the entire combo of LCA and upright over to a hydraulic press (bring to it my place in south durham if you need access to a press) and then press out the frozen bolt. Or, once you have the LCA + hub out of the car, you might be able to position it in a way that you can really hammer on it with a strong punch.
This also assumes you don't run into similar frozen bolt issues when you try to remove the LCA from the subframe!
Or you can try heat + hammer. My fear with the heat approach is I would be concerned about overheating the hub/upright as it houses your wheel bearing.

I hate crap like this. It is so much easier when it all just unbolts like it should.
Richard
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Richard Casto
1972 Porsche 914
2013 Honda Fit Sport
2015 Honda Fit EX
http://motorsport.zyyz.comMoney can't buy happiness, but somehow it's more comfortable to cry in a Porsche than a Kia.