Yes, Scalex is a Pyrethrin based product, so pretty much like Permethrin based poultry dusts, the concentrate of Scalex is a bit less than the others, but it *should* be fairly effective in killing the active lice.
I've never used Elector PSP, but do hear good things about it, it may kill the...
No, not the eggs.
Use your crisco or coconut oil, to help work loose the nits (egg casing) from the base of the feathers.
Use the Permethrin to kill any that hatch.
I'd get some Permethrin poultry dust and dust all the birds. Get some permethrin spray and treat their housing, making sure to get into nooks/crannies, roosting bars, nesting boxes, etc. Clean out the bedding before you treat the housing.
Repeat in 5-7 day intervals.
Scalex can be used, but...