hey, ill try and help with as much as i can but a more experienced member can help you more. ill do my best though :D
1) for my cories and plecos i use just algae pellets and they absolutly love them, they usually hog one just for themselves
, as for algae wafers im sure it will do the same job. as for the brand i cant help you out there as my lfs only stock one brand, but it might be helpful to try a couple of different brands, but i dont think they are that much different.
2) i also had this problem, but i took a suction cup that came with the filter (which i didnt use), and when i put a piece of zucchini, or cucumber, i cut a little rectangle ( to fit the end of the suction cup) and then twist it so it works as it would if i were to put it on my filter. im not sure about the fork though
good luck with your little guys :D