This version is a success, but:

• The firmware for PIC10F202 could be written in C instead of Assembler. I will try to rewrite it.
• The whole idea of changing what is shown on the display using a D-type flip-flop + analog multiplexer doesn't work, it's overcomplicated and overpriced. In the future, I will just use two LCD modules. They are cheap.
• It takes time to solder and protect (using hot glue) the connectors for the potentiometer, humidity sensor, and LCD display. Also, hot glue everywhere doesn't look very professional :) I plan to use Micro JST-XH connectors instead. There is also pinces-like tool to form cables for it, I don't know the name.
• The 4017 chip + bargraph works (for showing how much water will be dispensed next time), but I have found a better way. The same can be achieved with a CD4026 + 7-segment display. The CD4026 is nice because it only needs pulses to be driven, so only one GPIO is still needed for it.
• In the meantime, I have found a nice open-source project called Topola - it's a topological router. I will use it in the next design. The PCB is simple, so it's a good sandbox for it.
• I have also found the KiBuzzard add-on for KiCad, which should be great for labeling test points and connector pins.
• KiCad has a connector for a PIC ICSP programmer (component name: Conn_PIC_ICSP_ICD). I will use it so that the programmer can be plugged directly into the board—no need for jumper wires, which are error-prone.