Fellow newbie here as well. The only concern I would have with the maters is their high water content.

If your bin is on the wet side you may wish to limit the amount, but if moisture levels aren't an issue, then why not?

will work fine - chop them up and mix with some drier material like shredded paper, leaves, or sawdust, or crushed grains and add in one corner so they don't soak the whole bin

Bill