I don't quite follow your characterization of the 110 activation. Or perhaps I'm starting to but it's interesting wording. I would definitely avoid throwing around the word hard fork when chainsplit is what you mean.
The solid happens when you have a chain of blocks. Let's call regular blocks a, and 110 blocks b.
a-a-a-a is where we start.
If, at activation, the first block mined is NOT 110 signaling, you immediately get two chains. One at a-a-a-a|-a (legacy), and the other at a-a-a-a| (RDTS)..
A 110 block being added will give us a-a-a-a|-b on RDTS. Add ANOTHER one before legacy gets a block and we're back to one chain, at a-a-a-a|-b-b, as it's now the heaviest chain.
Hard to type this on a phone and I feel like I'm being a bit pedantic here so apologies if so. Guess the point is that it can split or not without any rolling back of the fork. It is true that rolling back a soft fork usually does require a hard fork (taproot would AFAIK) but RDTS has a sunset built in -- the rules only apply for a year.
https://forkalicious.supertestnet.org/ is an inteeractive tool for exploring possible reorg scenarios that can be helpful.
The interesting thing is that if you don't transact amid this period you don't really get forked off -- you just get utxo's on two chains instead of 1. If you DO transact though your tx could be reorged, or your coins replay attacked -- this is where there's a fair bit of danger. To say nothing of possible issues with lightning channels if one peer is pointing to legacy while another points to the RDTS split.
Anyway, on another note I'd also say economic node rather than merchant just as I see it used more and it's a bit clearer.