Can I run Nobby Nics tubeless with sealant.
Schwalbe tyres seem to seal ok from what I've seen so yes
you may find that a tubed tyre with sealnt weighs less than the equivalent tubeless without sealant (and most people run tubeless tyres with sealant anyway).
Yes, but… Proper tubeless tyres have tougher casings, so are more resistant to pinch punctures, the main reason we run tubeless in the first place no? (that said if you don't ride anywhere rocky, normal tyres pumped up firm with some sealant in is fine)
or i could buy 2 X 20" BMX tubes and go ghetto.
If you're happy with the idea, then do it… It's not as quick to do (first time) as many people make out it is, but the results are very effective. For the price of 2 BMX inner tubes (bought mine for £2 each from Sainsburys, and they had removable valve cores!) you can't really go wrong. Though be careful that some makes of tyre work better than others, Kenda like you have are not known for their reliability when run tubeless… Maxxis, Bontrager and a couple of others are MUCH better.
im thinking ghetto would give me the best result. but do i need presta removable valve cores?
or can i get away with schraeder (fit my rim better) and then unseat the bead, pour in sealant, re-seat bead, inflate?
Schraeder are fine, though preferably with removable valve cores as removing then reseating the bead when you've got a piece of BMX tube to reseat it onto, rather than just the rim, is a royal pain in the arse… Trust me on this one!
and i assume that if i go ghetto, id only need bog standard rim tapes, rather than the tubeless yellow stuff? as theres sort of a tube in there?
Yup. Depends on the rim/tyre combo you're planning to run as to what you might want to use. If you're using loose, non tubeless tyres, you might want to run a couple of layers of rim tape. If you're running proper tubeless compatible tyres (like I am with my Bontrager ACX's) then I can suggest using the thinnest stuff you can find. I used electrical tape! All it needs to do is cover the spoke holes after all… Still my tyres were a pain in the arse to get on though, but once on they did seal pretty much instantly.