The types of top coats that you can use on polymer clay should be fine to put back into the oven. I've asked a few skilled crafters about this and they've all told me this is okay. I frequently under back my polymer clay, paint it, glaze it, then put it back into the oven. I also find that pieces are more durable and less likely to chip (I make jointed pieces so rubbing is a factor for my work). I use triple thick and craft matte varnish (in a spray can), and I haven't had any problems with them in the oven. This is because you should only be using water based sealers on your polymer, nothing with oil in them (which are the ones that are flammable and therefore dangerous to put into your oven).
Have you considered painting them instead of using coloured polymer? It adds a step, but it might be easier than finding those colours. I live in Canada, and work at Michaels and I haven't seen the new colours at my store yet.
Some of the tutorials I have found online for Monster Highs use air brushing, but usually for small details and bit shading.. For doing it on a whole body I think it would work you might have to sand the joints a bunch after though (which you have to do sometimes anyways after you take them apart or mix them up, I totally wish that I had one to try it out. Especially if you wanted to do cool effects of fading between colours.
E6000! It's my favourite glue to buy. You don't need to mix it like epoxy glue, but it is still industrial strength and super affordable. I've had things glued with super glue and other types of non- epoxies, and things fall off, but I've never had anything fall off with E6000. Or, if you can find some (that is affordable) silicone. (my problem is that I can never find silicone in regular stores in Canada, only speciality and model stores where it is more expensive than I'm willing to pay).
Great work! I totally understand the literal pains of lino cutting (my hands have been cramped for days from it gah). For a few tips for printing without a press: For shirts, have a shirt form that fits inside of the shirt, it keeps wrinkles out of the fabric, keeps it overall flat, and I find makes it easier to do a bunch of shirts in a row (assuming you have a few forms). You might want to try adding a medium to your water based ink, think will make the transfer go smoother (especially onto paper), such as a retarder (which will also make your ink dry a lot slower, which must be causing you some troubles if you are doing more than 2 or 3 prints at a time), but you can get other bases and mediums to mix in. Also, I use a second (wider) brayer to print, it gives a bit more of an even result than other ways that I've printing without a press (although I'm not sure what you are currently using to print so maybe you already are using a brayer?) But, for smaller blocks, I use a piece of thick glass for pressure, which I just find faster for little guys than the brayer. I'm not sure how using a piece of glass would work for larger blocks, I haven't had a piece big enough piece of glass to try.
Also, I saw that you printing using your car as a press.. so smart! I don't own a car, so it totally doesn't work for me, but if I had one, you could bet a bunch of my gas would go towards using it as a press, instead of all of my gas going into hand pressing (hah).
I second using the gel medium, but why are you deciding to glue fabric to the canvas? (I'm sorry if maybe I missed some detail about why) Was the canvas stretched before with staples? If so, it would be easier to get a new stretcher frame and re-stretch it (and easier on the art) than it would be to try to attach fabric and wood with glue. Plus canvas can sweat and collect moisture, which is why they usually don't have glass on them when framed, so they can breathe the fresh air, by putting fabric and wood directly over the entire back, you risk providing the canvas with an area to collect moisture and grow mould. Also a random little fun fact, if you want to clean the surface of the painting, use a piece of white bread! It is soft and will actually absorb dirt, oil and other nastys that have collected over the years.
Thank you for the kind replies.. I have a quick question for anyone still around: Should I have posted this in the polymer clay board? I honestly didn't even notice there WAS a specific polymer clay board until today, or does she fit better in the toys, dolls and playthings board?