First attempt at a single/fixie conversion

Confirm the BCD, then have a browse through eBay: you never know what you'll find...

You could re-space the hub, by moving any spacers from the DS to the NDS, to shift the hub outboard to increase the chainline. But then you need to re-dish the rim, so it's central in the frame again.

Easier to use the BB to adjust the front chainline to match the rear. Spacing the chainring is only for fine-tuning: I wouldn't want to be putting torque through something at the end of too long a lever.

You could browse through Velobase in the hope of identifying the Peugeot cranks. You'd then know what the size of the original BB was and could calculate what size the new one would be, assuming the position of the chainrings followed the road double standard (I don't know if things were different BITD and the French tended to do their own thing then).

But there are so many of that style of crank, I don't fancy your chances: everyone made that style, which is a copy of the Campag Super Record crank.

However it's always preferable to measure what you actually have in front of you, than rely on what the internet says. Fit the Pug cranks to the BB you have in the frame and measure the chainline of the big ring. Once you know how much it needs to move, you can also check that it will clear the chainstay.

You're welcome, but just because I'm the one shouting loudest, it doesn't mean I'm right: confirm what I write yourself!