So does the Kushy Amino acid and it will work out cheaper. Kushy you use like 2ml - 4ml per 10L of water.
Umya you use 100ml per 10L and is more expensive. Go with the Kushy, @Prom has done side by side trials with Kushy amino vs Bio-Heavan and found little to no difference.
I use this for my plants and works great, however these guys are cheaper - https://gthydro.co.za/products/897-captain-black-strap-1l.html
In veg you only going to use like 2ml per 1L water, feed once a week. I usually combine this with some calmag.
In flower you can go up to 4ml - 5ml per 1L water, I still use it in combo with calmag here.
one extra addition I would recommend if get a bottle of microbes - https://hydroponic.co.za/hydroponics/biodyne-environoc-401-microbes/
Add some microbes in at 0.5ml per 1L water, feed once a week, this will keep introducing new microbes into the grow medium.
You can stick with Seagro if you using the molasses, it will be much of a muchness.
Yeah those are fine, just keep in mind that you need to stop the humic acid from 3 weeks into flower (it can bring down terpene levels if given all the way through flower). Fulvic you give a little bit in veg, but more as you progress into flower.
So it's not essential, but does help.
I use Kelpak - https://www.greenhouston.co.za/products/kelpak - I only use it once a week, but its heavy on application with 5ml per 1L water, so I tend to go through it rather quickly. 2 or 3 bottles might be needed over the course of the grow.