OP, the thing about spelling isn't just other posters being snobby or poky. There is sociological research on the effects that names have on a child's educational attainment and economic prospects as an adult.
The book Freakonomics has a chapter on this, worth reading. Some disparity in later achievment is due to the fact that traditional spellings are more often chosen by well-educated parents, and alternative spellings and misspellings by less educated parents, and a parents' educational level will have an impact on the child's prospects anyway.
But even after adjusting for parental education and income, children with non-standard names had worse prospects. Identical CVs sent to employers from Jasmine and Jazzmyn, Michael and Micheal, Amy and Aimee showed that in each case the person with the traditionally spelled name was more likely to be called to interview.
So you might like the alternative spelling, but it's worth considering the longer term implications for your child, starting with the preconceptions that health visitors and then teachers will have about your family, and then your child's job prospects.
I think Malachi is a fabulous name though