@samanthag46 yes peanut butter is ok but preferably a natural one without added sugar, you'd have to test the toast so test before eating and then 2 hours after, ideally with no more than a 2-3mmol rise
Plain greek yoghurt is better as muller light has no fat to slow the absorption you can however try to slow it by eating it after a meal with a decent fat content, but again the only way to know if you can handle certain things is to test before and 2 hours later
cheese/cheese spread should be fine, nobody can say yes/no about crackers apart from you by testing
A lot of us on here eat the Nature Valley Protein bars as at less than 10g carbs per 40g bar they are great, available in 3 flavours - peanut & chocolate, salted caramel and almond & coconut x