For adult pigs (over 1 year of age), a grass based hay should be the primary hay. This can be meadow, timothy, orchard, etc. You can feed orchard and meadow in place of timothy and give them unlimited amounts.
Oat hay is fairly coarse and I do tend to limit it, primarily because they eat less of it and you can't buy it in large amounts.
Alfalfa hay is fine for young pigs (under 1 year of age), but the calcium content makes it inappropriate for adult pigs, as it can cause they to develop bladder stones.
The botanical hay isn't dangerous for them, but as you saw it's pretty expensive, and it doesn't provide any benefits to them other than having the additional treats in it.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry