Use philadelphia/own brand soft cheese rather than dairylea, it's less processed. I wouldn't offer jam but that's mainly my own food snobbery!
One thing to be aware of is that 100% fruit jams usually use low nutrient fruits (all the bad looking stuff that you wouldn't but in a packet) and a ton of fruit juice. So although the sugars are good sugars (as opposed to artificial sugars) jam on regular basis is still pretty sugar-rific.
On top of ones here I also do egg "mayo" (the mayo is a smudge of soft cheese), beans/cheese on toast, various meats like chicken (they love chicken and sweetcorn)/ham/beef/sometimes sausage etc, grated cheddar cheese, hummus, prawn.
Also try rice cakes (mine love Marmite and hard cheese - bleugh!), wraps, pitta, toasted versions, quesadilla etc for variation. I occasionally give crisps but alongside cucumber, carrots, baby tomatoes, pepper, fruit etc and also a crisp that it just potato with no added anything (like kettle crisps).
Omelette, small jacket pots, bagels, eggy bread, egg and soldiers and falafels might also be feasible?