Unfortunately, the chemicals involved are too complicated for a simple assumption like that. LSD really doesn't do anything with serotonin that would be expected to dampen the impact of MDMA. Calling LSD a "serotonin analogue" is already a pretty big stretch.
I do feel that it should be pointed out though that DOI and 5-MeO-DMT have very high efficacy for 5-HT2A, whereas LSD is a low efficacy partial agonist. I would wager that it's possible that LSD could actually work antagonistically in this way and inhibit the neurotoxicity. Of course, we will never know until someone tests that specifically.