PowerApps Application Modification

We use a PowerApp application for logging water testing.
This is linked to an SQL backend. Not on Azure.
The application works well, however needs some modifications. It has been working for several years without fault.
The minor modifications I think would benefit this application are:
1: It calculates amount of chemical or a corrective action to take. At time of writing these are sent to SQL as notes. I want to change this so the user ticks the actions taken and only those are sent to SQL.
2: As it stands I can look at the last water test in the system. I would like the option within PowerApps to look at a water test earlier in the day to see what the recommendations were. This way if say it calculates 2 kg Sodium Bicarbonate to be added and I am doing it later in the day I can look back and see the amount and what and tick to add it now.
3: Consider incorporating a task list by the water body by day so the guys doing the work can actually tick off the tasks to say they are complete. This may not be pursued as it may be too costly to consider.
4: If 3 above is possible can we incorporate time cards into this app?
Thanks for the interest.
Please ask questions if need.