Enid, they sell Glycerin and Rosewater here for very little at the pharmacy. My grandmother has a giant tub of it and uses it as moisturiser, I don't know if the baking stuff is the same as used for cosmetics but if it's safe enough to eat and has no other ingredients I assume it would be safe enough to use on the face mixed with a bit of rosewater.
Lego, so far the reviews I've seen seem to say that PC's Niacinamide is a bit better than the Ordinary one but not enough to justify the price difference. I think it's more of a how much do you want to spend on it question, I'm guessing texturally the PC will be a bit more light weight and frugal in use (TO is a bit gloopy).
Wilting, I have no clue how to convince you of the greatness that is acid toners. I used pixi glow tonic with trepidation and it really soured me towards them as it really didn't agree with me, leaving me convinced acid toners were evil. However, when I did a bit of research you'll see you've most likely been using something with Salycilic, Glycolic, or Lactic Acid and liking it very well, most likely due to their presence in it. When you have the right acid toners they are truly game changers in a routine.
Pupsie, no payment necessary, feels like I'm running a Ponzi scheme if I start charging for decants. SC make the samples and sell them to suppliers in a box of six, they're not supposed to sell them on, just push the single bottles on interested customers. The trusted seller is this one. Helpfully they let you know when it was produced too so you're sure you're not getting old stock. I am calculating an import tax on top though as you never know, but I will ask them to mark it as samples which they technically are and should therefore be exempt from taxes.
SuperFly, you're already using an AHA in the Good Genes in the form of Lactic Acid. If you're interested in a Retinol there's not much out there in the 'natural' world, something like Sunday Riley's Luna Oil (Nabootique if she's still around uses it and likes it but reviews are very mixed, mostly as it was pushed at a far too young youtube audience and it has quite a specific place in your routine that wasn't intuitive iirc). Kypris Moonlight Catalyst is another that comes to mind but the brand has some very odd behaviour towards its customers as chronicled here and again, Nabootique used a few of their other products and was left unimpressed, especially considering the price tag.
As for your friend who has drunk and smoked, is that still ongoing? Retinol is the first line of defence, I think the LRP Redermic R for eyes is probably a decent budget choice but have no clue how effective it is as it's very much a love it or hate it product. Otherwise I use Verso Super Eye Serum which I find brilliant but I use preventatively so I can't say for certain how it fares as a reversing product, reviews are good though and despite the high initial price it lasts very long and is twice the size of a normal eye product so works out a bit more reasonable. Will take a while though to see actual results.
Lego, I tend to rub quite small concentric circles with the pads of two fingers and then swap out to two knuckles and linger in one area counting a good number of seconds. I've also mixed in the BHA with the clay mask sometimes. I think it's a good technique, it doesn't however surpass the (albeit temporary) effect of the Glamglow supermud mask, but I always balk at the price as the jar dries out quite quickly and I'd only ever use it on my nose so surely would be throwing out half a very pricey jar, I think in the UK it's easier to purchase the smaller tube sizes (at M&S) but I can't get my hands on those here without incurring ridiculous shipping charges.
Yes Vit C takes a while to notice effect, though the marginal hydration benefits and expedited recovery period post blemish should be noticeable. I've been using Vit C for so long now that for me it's more a comparison between products than looking for effect, iyswim.