Does it matter if you place resistors horizontally or vertically in layout? I know for transistor it matter but how about resistors? Basically what is the rule of thumb for placing resistors in layout
Make sure transistors and resistors in Bandgap have the same orientation with resistors and transistors in current sources.
Resistors could be vertical or horizontal. It'll be better to have them in direction with less tolerance, of course depend on your technology.
Added after 1 minutes:
You may need to use true table to matching resistors
for the PNP matching
Make sure the resitor the designer use in the bangap is the same as those use is the other circuit. Example: gate bias for frontend.
Since this is a analog circuit, if there is op-amp inside the circuit, the symetrical of the diff amp will does matter. the input path of the both op-amp is better to make it same. Different length will have different resistance, and this will coz some offset to your op-amp.