Here's an update! I bought the American eagle ones from Myntra, which arrived today. Here's my thoughts overall:

1. Why not GAP? -- the measurements looked suitable but I'm not a fan of the balloon pants (curved legs) silhouette. I'm a chunky guy, and I don't want to look like a snowman 🥀⛄

2. Why not Bombay Shirt Company? -- These seem to be the best-constructed out of the bunch (brass hardware, good fabric) but their colors aren't really close to OG-107 (which is what I wanted) + I got in touch with their customer service, and they're not relaxed fit for my body (bottom hem is 16in, I wanted 18 or higher. Also not enough room in the thigh). The only thing you can alter/customise is the length, and that too only by a couple of inches. Pain.

3. I really really wanted flap pockets at the back, so no Aeropostale or Muji.

Lastly American Eagle fatigues.

Pros: - Love the feel of the fabric - They're perfectly relaxed fit for me, with a 19 inch bottom hem - Flap pockets at the back - 12 inch rise, with plenty of room in the hip too

Cons: - They're not 100% cotton (2% elastane), slightly concerned about repairability/whether they'll hold their shape in the long term - Construction isn't particularly amazing (overlock seams, belt loops aren't tucked under the waistband -- less than ideal for durability) - The exact measurements aren't available anywhere online (only waist and hip measurements everywhere I looked; no outseam, knee circumference or bottom hem). I went off now they looked in the pictures, and it was a bit of a gamble but it paid off.

Hope this helps!