Can you ID this wood? (plus stripper vs cleaner post-sanding)

1. Northeastern Minnesota (near Lake Superior's North Shore, 20 miles east of Duluth)
2. Full sun
3. Can you tell me type of wood? (see pics),
4. No mold
5. Recovering from ramifications of previous owner's application of Deck Restore or similar thick grainy/mastic coating, with solid stain under that (found old bucket of Behr Premium Solid Weatherproofing Wood Stain from 2010, but that might have been for the siding). Put at least 50 hours into scraping it.

I've scoured your site and think I have a solid plan of action. Thank you! Winter is around the corner here. I plan to replace the missing/damaged boards now, set raised nails, and do as much sanding as I can before winter sets in. Leave bare for now. Re-finish in the spring with RAD stripper or cleaner (using pressure washer), then brightener, on everything new and old. Then stain. I already have samples of RAD and Armstrong & Clark. May apply samples to one of the removed boards after sanding/cleaning/brightening to test weathering over the winter.

My main question for the experts is whether you can easily ascertain from my photos what type of wood the originial deck boards are. I'm pretty sure they're 5/4 PT, but wondering if they might be cedar. A previous owner put in some replacement boards that are visibly different...maybe 2x6 PT, as the edges are more squarish (the grain is also more defined). The originals are rounded and slightly narrower & thinner. I'd like to replace the replacements with boards that match originals. What do you think? PT or cedar?

This photo is all original boards, scraped down:

These photos show how the replacement board sticks out like a sore thumb:

Close-up where you can see remnants of older solid (dark brown) stain and newer thick Restore-type coating (light gray/brown):

Here's how it rotted (older rotten board sitting atop newer replacement board...notice the difference?):

Overall deck (taped boards are the ones I'm replacing):

There are more photos and videos in this OneDrive folder:

1DRV.MS "https://1drv.ms/f/s!AggjqGvzdoCR5livAt1HtAGPiiBH"

Microsoft OneDrive

Also, I already purchased RAD stripper & brightener package. That was before I "finished" scraping and realized I'll probably end up sanding much of it too. Can I just "clean" with the stripper in the spring, or would it be better to buy the cleaner instead if I've already done a lot of sanding?

Thank you so much for sharing your expertise!