Track bike to Single Speed - Questions

[pdonk]

As per another thread, I rode my track bike a few times on the road this year, and found I really enjoyed it. It got me thinking about converting it to a single speed next summer, once track season is over.

A few questions, can a freewheel fit on a standard track hub or do I need to find a 120 hub that is single speed specific? I understand that the thread is the same but that it may not engage as much, any concerns?

The rear is not drilled for brakes, anyone have experience with adapters such as https://www.retro-gression.com/produ...te_7alZLtmTlts

Other than being ugly, do they work?