Her feet are on the mend. They are still by no means completely balanced but boy are they looking better, and she feels better.
(Links to the before photos of her hooves 001 & 002)
Our farrier basically confirmed my thoughts. Havana's feet being neglected and improperly trimmed, thus un-balanced. She started cracking and some nut job farrier thought hacking a line across the crack, rather than fixing the actual un-balanced issue, was the way to go to keep the crack from heading farther up the hoof. Thus the tic-tac-toe look. Now, I've heard of that being done before, to prevent further cracking, but these were deep gouges into the "outchy" part of her foot. There was also a considerable amount of busing.
They are now being corrected & already look so much less painful...
Havana is feeling much better too now that we had those nasty feet taken care of :) She is running and playing.
We took her for her first ride, which she (to no surprise at all) was perfect for. She followed along down the trail quietly like she has been riding for years. This is such a sweetheart of a horse!
A few more pounds, some riding muscle and a couple more trims then she will be as good as new....