Would it be possible to set up a Bitcoin Core pruned node and attach it to one of the existing lightning network node implementations, or does one need a full (archival) node?
You can use a pruned node if you choose either c-lighting or LND. However, whichever you choose, you need to be careful about the discrepancy in the reported blockheight by your Bitcoin and Lightning nodes. If your Lightning node crashes for some reason and your Bitcoin node prunes a block which has not been processed yet by the other node then your Lightning node will get stuck. See the following links for more information (
#1,
#2).
Also, what lightning node implementation is compatible with the Bitcoin Core software?
c-lightning, LND, and eclair which requires non-pruned nodes.
