At first I thought the question did not make sense. As RogerP pointed out, the most comfortable shoe is the one that fits you best. If a shoe really fits, it doesn't matter if it's an oxford, a blucher or a Chelsea boot.
If you mean 'most forgiving' or 'safest', especially when you buy something on the Internet, that's a different story and your choice actually makes a lot of sense, except that suede might still be better. If you buy without trying on, I'd be cautious about oxfords and double monks, very cautious about Chelsea boots and would ignore loafers altogether. So, yes, boots (any kind of boots except for balmoral) in suede might do the trick. In fact, you can just err on the larger side and, if necessary, adjust the volume with sock thickness. But 'safest' is not the same thing as most comfortable.