Seeds produced from autos.. viable.. ??

All fem seed comes from a plant that hermied... that's the only way to cross XX with XX to get 100% female seeds. Whether or not there is an elevated risk of hermie is context dependent... probably a higher risk here, but it was only 4 seeds.. not like it was a major problem. I'd wager it's better than 50/50 they turn out okay... i'd be curious of the results for this sort of thing, not that the 4-seed sample is suitable, but still interesting.

No, they will not be feminised.................pollen came from a hermaphrodite flower.................your seeds will carry dominant genes for being hermaphrodites too. Feminized seeds are basically created from chemically altered plants with chemically altered genetics.........none of which occurred in your situation. If you grew 2 autos of the same strain, there is a chance they may be like their parents.............but since nearly all modern cannabis is a hybrid of some sort, genetic recombination can throw up absolute random genes, meaning your selfed seeds could turn into anything, including plants that now have previously undesirable recessive genes that have now become dominant (high chance). They will be autos though, as there was no other pollen source. All in all, if you have lots of space to experiment and are prepared to accept failures, continue growing them, but I would advise against using them as your main crop and relying on them to produce guaranteed, quality flowers. The risk of hermies and the risk of bad genetics due to inbreeding is too high in my opinion (and experience) and I would suggest growing commercially bought seeds that have been stabilized by the commercial breeder.

seed viability is mostly about age and how they were stored. So, they should be ~100%. "Probably" a higher risk of hermies, but that depends on more than one factor. 4 seeds is not a lot, so it's not like they had a severe herm trait to start... maybe even local stress caused it, which means it's less likely passing down an undesirable trait. XX x XX will always provide female seeds as long as there was no other pollen contamination. A Y chromosome can't spontaneously manifest. If you have nothing better to do, it's fine to be curious, but if a failed crop leads to major problems, better to play it safe and avoid these seeds... all a matter of context.

If you get seeds from a previous plant - it mostlikely self-polluted. which makes the chance of getting a hermie like 99.9% (its not adviseable)

Most likely hermies, but will be autos.

The seeds should be feminzed autoflower seeds yes. But I think the chance is higher to get a hermaphrodite from the seeds you harvested. You can try them, maybe you are a bit lucky and they grow perfectly well :)