Hi,
1. There is no option to do that for now. For categories, I wouldn't recommend to use a filter. Instead use a categories listing module. HikaShop has a 1 or 2 level module for that. And If you need more levels, you can use for example this module:
extensions.joomla.org/extension/skyline-...cordion-for-hikashop
It can handle as many levels as you want.
That's some reasons why we didn't focus our efforts on categories filters until now since you have some possible alternatives.
2. There is no option to do that for now. However, if you use an ajax Joomla search module with the HikaShop search plugin, you can achieve a dynamic text search field. The drawback is that the results will be displayed by Joomla, not HikaShop, so it will be less nice.
3. There is no option to do that for now.
4. Please understand that the explorer selector that we have in the backend was only added less than a year ago and I took us already 6 months to make it available everywhere in the backend. Next step will probably be the filters/custom fields for it, but we've been working on a whole new checkout system for the past 6 months and are still working on it so other things have been put aside for now to focus on that. So I can't say what we'll do when regarding filters. It would be lying to tell you anything else. However, we do appreciate your feedback on that. It will come in handy when we finally have the time to work on the filtering system.
5. There is this extension for filtering for HikaShop:
extensions.joomla.org/extension/cherry-picker-for-hikashop
It might be able to answer some of your needs.
6. To go further and be able to do all you want with the filters system of the current version of HikaShop, it would some extensive custom coding. I would recommend to contact our partners about that:
www.hikashop.com/home/our-partners.html
Several of them should be able to provide such customization. The price will depends on how much they charge and the extent of what you want them to do so I can't say.