You can send with a 1 sat / vb fee which will probably never get confirmed at this point.
You can't really, at the moment. Given that the vast majority of nodes run with default settings, anything below around 2.9 sats/vbyte at the moment will simply not be relayed, let alone confirmed. You could of course manually connect to a specific node which has increased its mempool limits, but then your transaction will just sit in the mempool of that one node and not go anywhere, which obviously achieves very little.
There are a fair amount out there that do. I just did a check since I am taking one of my LN nodes offline. I saw the tx in my wallet. I then did a RBF to get it confirmed.
Probably would have dropped / disappeared within minutes.
Either way it's still the same point. Sending with 3 sat / vb will show up and probably never get confirmed.
Or, you could also send with a low fee and then send another TX out from there with a low fee and then RBF the parent TX.
No matter what it's still sketchy for the OP to ask.
-Dave