Personally I wouldn't add to Harry Hamster. It contains everything needed in the way of vitamins, nutrients and protein and it can upset the balance of a mix if you start adding things. What I did instead was add the extras as treats - but not in the food bowl - just now and then, scattered or on a separate dish. So as well as the daily veg I would give the occasional fresh treat or seed - eg the occasional nut (half walnuts are popular), piece of apple or blueberry eg and some scattered pumpkin seeds occasionally.
Having said all that - if you're planning to get a dwarf hamster, it would be better to get a dwarf hamster specific mix instead of Harry Hamster. There are two good ones but they're only available online. They both already have a really good mix of good ingredients and variety. The Bunny one from Zooplus - is very good. Zooplus only do a minimum order of £15 so I used to get 3 bags at a time - and then they last a very long time! Rodipet also do a good dwarf mix. The postage makes it more expensive though. Theirs is organic though if that makes a difference. The Bunny one is a little bit low in protein so giving the occasional protein treat would be good. eg a bit of scrambled egg, a nut weekly, some freeze dried chicken. This mix contains mealworms as natural protein which hammies like
https://www.zooplus.co.uk/shop/small...d_bunny/620085
If it's a Russian dwarf hamster, they are all hybrids (unless you get one from a breeder) and this mix is specifically for hybrids (who are prone to diabetes) and has the correct protein.
https://www.rodipet.co.uk/pet-foods/...nior-500g.html
If it's a robo then there is a standard dwarf hamster mix from Rodipet
https://www.rodipet.co.uk/pet-foods/...nior-500g.html
The protein in that is pretty good, only slightly lower than Harry Hamster so the occasional nut treat should do the trick.
So you wouldn't need any of the ingredients you listed above if you get one of these good dwarf specific mixes and could just supplement with a bit of veg, the occasional fresh treat (they like any fresh food usually but there is a "safe list" on here).
I wouldn't give chickpeas, or the other beans listed mainly due to the size and they can also get too much protein.
While it's not good to take things away or add them to a mix really, I did used to scatter 2 or 3 of these all in one pellets as well as the Bunny mix - it contains everything needed just in case they didn't get the balance from the mix and helps with supplementing protein as well.
https://www.amazon.co.uk/Supreme-Sci...1603435&sr=8-1