In general, if I just read your questions, I don’t think the TP-7 will do what you want right now.
Having said that -
No, it’s not possible to get perfect loops or even loops at all, more than looping playback of entire tracks. If I’m gonna guess, I would guess it’ll get looping at some point with overdubbing, but tight midi loops for say rock solid sequenced layers, I feel is less likely.
No time line arrangement. This also feels less likely. TE doesn’t position this as an arranger and composer, but more collector of ideas or demos.
I’m not sure about duplicating, but you can overdub and it’s very simple and straight-forward. However, with six stereo tracks (potentially, depending on how you connect it), overdubbing isn’t always necessary. You got plenty space to just split up all the tracks and perhaps merge them later into say the OP-1, as you suggest.
No channel streaming from TP-7 to OP-1 or the other way around. This, I feel, is more likely to happen at some point, though, since clearly the TP-7 can channel stream. But only with the TX-6, so far.
No digital tape effects, except playback speed by adjusting the pitch. That. however, is quite granular, much more so than the OP-1, and I really like it. I tend to use it even for subtle playback shifts up and down, to get just a hint of tape-like effect.
Overall, you should look at it like a collector of ideas and demos, and then as the multi-tracker part of the Field system together with the TX-6 mixer.
On paper, it’s nothing special, really, the only thing that makes it stand out in functional terms is the size and battery power (it’s rechargable) and it’s somewhat limited but powerful streaming features, if you got an TX-6.
But most products aren’t their feature list on paper and this is more true for the TP-7 than for most products. The way the workflow is designed, the streamlined process of just capturing and recording stuff, the combination of size and features, makes this into something else. It doesn’t compare to other field recorders or similar.