The liquidity doesn't disappear if you swap it, it just moves from local/outbound to remote/inbound.

Like, you open a 1m sats channel and have 1m sats to spend and 0 sats to receive, 
you swap those 1m sats to pay off your loan and then have 1m sats to receive and 0 to spend.

Doable, but just buying a channel with inbound liquidity might probably be cheaper than tx-fees + ln-fees + swap-fees + loan-fees. 

 Thanks for this explanation.  If one uses foreign liquidity, and they go out of business, the seeds can be backed up and restored on a new node? (to not lose the L2) 

 You can (and should) backup a channel, yes.
You might still "lose the L2" when using such backup due to the channel being force closed, but you'll get your remaining local sats back on L1, so you're not actually losing anything (except maybe Tx-fees for the channel-close).