Well I guess I'm going to be the downer here and say that he probably shouldn't have these things until he develops the pincer grasp (thumb and forefinger) and can pick them up and get them in his mouth himself. this grasp usually develops between 7 and 9 months.
He doesn't really need teeth to chew, babies/toddlers don't use thier teeth that way, they use thier tongue and the roof of thier mouth to mash foods. Graham crackers and cheerio's do melt/dissolve easily so they might be ok, but again you should wait until he cna pick them up himself. Raw honey is the only honey you need to worry about, Graham crackers and honey cereals (like Honey Nut Cheerio's) have cooked honey, so no worry of botulism in those, only RAW honey.
Saltines are a little harder to chew, and big pieces can break off of them and he could choke. I'd steer clear of saltines for a few more months.
And popsicles....why on earth would you give a baby a popsicle? Hmm, here baby, have a frozen sugar stick...? Yeah, again something else I would hold off on for as long as possible.
Try a mesh feeder if you are looking for teething relief or 'entertainment' in the high chair. You can put just about anything in them, my youngest always liked apple slices, peaches, pears, carrots, etc in the mesh feeder. It was a safe way for him to have fresh fruits and veggies, and the coolness of the foods made his teething gums feel better.
www.wholesomebabyfood.com is a great site for new eaters. We made all our own baby food for both kids and by 10 months they were eating table foods, around the time thier pincer grasp was really good and they could get most of the food inthier mouths themselves. Before that, I stuck to pureeing thier food or mashing it.
Remember too that breastmilk is the most important part of his diet still, so table foods or solids should never replace that.