It is possible to enable tags, yes. Is this something that would benefit the community? I don’t recall it getting much use in the old forum except as a joke.
No idea about the collaboration threads, may be a setting we have to enable.
The forum uses standard codes, so I imagine such helm guides already exist, but we could link to them if somebody has a good one.
So what you’re asking for is to just show the categories and not all the Latest/Top threads underneath that? That I’m not sure we can/should disable. 
Having a hard time with your issues cause I don’t even have a tablet to test on. 
Not sure what you mean about the lack of navigation tools.
If by partially implemented you are referring to the broken links, that is unfortunately the way it’s going to be. The old forum was under constant harassment from a hacker and we had to migrate to a new forum in the process of securing the site. The old forum, and thus the old links, no longer exist. The new forum uses a different structure, which is why old links redirect you to the forum homepage.
Because of this, there will be some growing pains, but over time the critical links will be restored.
Not sure what you mean by this. Maybe you loaded the site while we were in the process of changing something (we’re making tweaks/improvements here and there as they come to us).
With Discourse, things update in real time, but at the same time other changes require a refresh of the page.