Porto attractions help

The Bolhao market is closed for renovation.
With only two days, you might want to consider a walking tour. It would help you hit the highlights in a fairly short amount of time. I did a food tour on my last trip and it was quite nice.
The train station is worth a peak but you can see it in a very short amount of time.
Spending some time across the river in Gaia is fun and affords great views. You can take a water taxi to Gaia from Rebeira.
The Rebeira area is fun but there isn’t a lot to see. You see the bridge from this area and from Gaia. I’ve never walked across it. There are some nice restaurants but be discerning. Trip advisor actually does a pretty good job with restaurant reviews. Rua das Flores is a fun street with shops and good restaurants.
Unless you want to climb the Clérigos tower, it takes no time to view it.
For me, just walking around in Porto is most of the fun. It’s lovely with great food and, of course, wine.
Matosinhos is also a nice outing. It’s a town by the sea with great seafood restaurants.
I haven’t visited the other places you mention.

The Stock Exchange Palace is definitely worthwhile (IMO). As I recall, you'll have to book a time for the tour, and I found that very interesting. The decor inside (especially in the "Moorish Room" is spectacular.

I can't remember if it was the Six Bridge Cruise that I took but whichever one it was, I quite enjoyed it.

I also very much enjoyed the Hop On / Hop Off Bus tour, which goes across the river. A nice relaxing way to see the main sites while resting my back. I can't remember if this is the one I used - https://www.getyourguide.com/porto-l151/porto-hop-on-hop-off-tour-2-day-ticket-t3453/?referrer_view_id=e9c5cb8ca96392d7c51e177b9bea77d0&referrer_view_position=1 (there are others).

Porto is a beautiful city. Have a great trip!