Nikkor 20mm 2.8 replacement for DX

Shooting topsided I typically carry my 3.5 year daughter along with photo gear. Now I have 1 month old son to carry as well.

Since I want to keep both my children some lenses need to go away or be replaced with lighter and smaller alternatives

Back in film days I used to have Nikkor 20mm 2.8. Now I'd be happy to replace Tokina 12-24 with something similar to that Nikkor (its DX equivalent).

I mean:

-> very compact,

-> shorter than 20mm (about 13-14mm would be great),

-> preferably 2.8, but I could live with something darker,

-> decent image quality,

-> rectalinear *)

It's mainly for topside, but I'd like to use it as my "middle" lens underwater along with 10.5 and 105mm.

Is there anything like that available?

Also, is it true that Nikkor 20mm 2.8 is too soft on digital bodies?

*) maybe cropped FE is rectalinear enough when not shooting from very close?

You did hit the sweet spot.

The lack of good WA primes for DX is referred to by many as a heavy indication of the lack of compromise with the format.

I don't know of any Ultra WA prime on DX.

Options are:

Nikkor 12-24/4

Sigma 12-24mm/4.5-5.6

Sigma 10-20/4-5.6 (apparently there is a new bulkier one a little brighter coming now - /3.5)

Tokina 12-24/4.

On the bright /2.8 size only options are:

Nikkor 14-24mm/2.8 (HUGE but amazing lens, and you will keep it if you go FX)

Tokina 11-16mm/2.8 (77mm filter...)

I would suggest a nice baby stroller and a bigger lens, that's what I did at least.