I think it probably worked because you saved the Security Log/email options. In BPS free I am not sure if we are automatically saving all DB options, but that should be done if it is not already being done.
Check any custom code that you have added to see if it has a redirect loop.
Click the AutoMagic buttons and activate BulletProof Modes to see if that fixes it.
Yep, not sure why the captcha cannot be added in the sidebar on this BuddyPress site. At some point we will look into that.
I believe the size options were done in the best/optimum size order. 500KB is the best size to choose, 256KB is the second best size to choose and 1MB is the worst size option to choose.
Yes, in BPS free they are repeated instead of creating separate options like in Pro. ;) Just cutting corners to make development quicker on BPS free.