Hi! I just wanted to ask if what might be the effects should I set my baseline to a negative value?
(For context, we have a font with rugged edges and we just realized at a later stage that these edges could just be treated as overshoots rather them sitting at the baseline, so that they look aligned when paired with other fonts.
Is setting the baseline negative adviseable? or should we just move the glyphs down manually?)
Move the glyph outlines down. You can do this for multiple glyphs at once by selecting them and then running Path → Transformations. Set a negative Translate Y value and confirm with OK.
Thank you for this trick @FlorianPircher ! But I wonder what the reason behind why it is not adviseable to set the baseline to a value other than zero 
The baseline can be set to a different value than zero. That is mostly used to vertically align different scripts (e.g. Latin and Chinese).
If you have Latin letters, I would keep the baseline at zero and add big enough overshoot.