sorry for the difficulty, you kind of just have to comb through everything. >< i'll make an update with a hint for which rooms specifically you're still missing letters from to give a better idea of where to search
here's a list of all the interactions you need (spoilers for puzzle)
bedroom:
- mirror
- drawer
bathroom:
- plants (including the small one by the sink)
- toilet
living room:
- flower pot
- shoes
kitchen:
- knife rack
- fridge