yes, apple is too hard for a 8-mth old bb, better to boil it a while before you feed your bb
there are so many choices except apple & banana, eg. papaya, kiwi, blueberries, pear 啤梨, grapes, dragon fruit, cherries, watermelon, melon, etc......, you'd better to feed a little bit first to try if any allergy occurs, if no, add more next time, one more,try avocado 牛油果, it is really good for health
for yoghurt, I buy Paul's original favour full fat yoghurt, bb needs full fat not low or no fat ones and they'd better eat original favour not those with favour for adults as they are too sweet, I usually add fruits in yoghurt, bb should like it.