NOPE. Just nope. Sharks have now been verily jumped.
Okay... let us get things straight here... in no particular order...
Firstly... why would her ghost be lingering around if she committed suicide? Suicide is generally seeking to escape from the pain of existence. It doesn't even begin to make any sense that anyone who removed themselves from the mortal coil deliberately would have any lingering attachment to life nor any desire to stick around as a phantom.
Secondly... how much are we going by usual Japanese rules here? I forget sometimes that this is manga and totally Japanese, except for the occasional clear and blatant cultural markers (like the tallies or the food they serve or whatever). But it is pretty much standard Japanese ghost rule that... well... ghosts don't have feet. So the fact that Legosi wasn't dead was obvious the moment we saw his feet. His mother, however, is anyone's guess as she is wearing a long skirt...
Thirdly... I guess supernatural shit is real in this manga. I guess that explains how reptiles and mammals can hybridise, or for that matter how a society of furries that should have imploded on itself ages ago is somehow persisting in mimicry of a real human society. Don't get me wrong... from a character / plot perspective this is an excellent manga... but the background setting is flaky as a wasp nest.
... Well, some supernatural shit is real in this manga. It doesn't necessarily follow that just because ghosts are a thing, that all the bets are off for other shit.