Hi there,
Thanks for trying Podcast player.
1. Podcast player should work with any host (spreaker or any other). However, You may face slight feed updation issue with spreaker for few minutes. Spreaker server is having some problems with WordPress feed system. We have provided all details to spreaker team. You may ask them for more information. Complete details of the issue can be seen in following ticket,
https://www.ads-software.com/support/topic/rss-error-spreaker/
2. For categories, Is there one podcast or three separate podcasts? If there is one podcast having multiple categories assigned to episodes, then it is presently not possible to filter episodes by categories. However, in next update this feature will be available in Pro version. This feature is already developed and currently under testing.
Thanks,