The main issue will be that of the size of image circle the lens projects. Because tilt and shift lenses move the center of the image circle projected by the lens away from the center of the sensor, they require a large enough image circle to accommodate this movement without the edge of the image circle crossing over the edge of the sensor. Rather than using a lens designed for µ4/3, you should select a lens with a FF sized image circle. Using a lens with a manual aperture ring on the lens makes using it with an adapter much easier than trying to control it via the adapter if the adapter even has such a capability, especially if the aperture is controlled by a mechanical linkage. So either go with a lens such as the Nikon "D" series that have aperture rings, or a Canon EOS lens that controls the aperture electronically along with an adapter that enables you to control the aperture.
The Fotga tilt adapter you have mentioned does not include any functionality for controlling the aperture with either Canon or Nikon lenses, so a Nikon D-series lens with aperture ring on the lens would probably be the simplest to use. EOS lens apertures can be set with certain EOS bodies. If you manually select an aperture and then remove the lens while holding down the Depth of Field Preview button the aperture will remain set at the selected value. Of course this means you would also need access to an EOS body with a DoF Preview button! Without control of the aperture you are limited to whatever position the aperture is in when you start (presumably wide open if it was removed from an EOS camera when the DoFP button was not being pressed with the power on).
As for the "miniature" effect, you'll need a wider aperture for that, so that eliminates most variable aperture zoom lenses. And because the µ4/3 sensor size carries a crop factor of 2.0, unless you want to shoot from far away you'll need a fairly short focal length to get the same angle of view and look that can be obtained on full frame cameras with T/S lenses in the 45-50mm range.
Something like a 35mm f/1.4 or f/2 or even a 24mm or 20mm f/2.8. To get an idea of what focal length works for you, you can use a zoom lens without T/S capability to see what focal length you will need to cover the scenes you wish to explore. A constant aperture f/2.8 zoom might also work, but those are fairly expensive if they provide full frame sized image circles. There are a few APS-C f/2.8 zooms that are relative bargains, such as the Tamron 17-50mm f/2.8 Di II, but the smaller APS-C image circle, though larger than an µ4/3 lens, would limit the amount of tilt you could do before vignetting begins. A µ4/3 lens requires a 21.6mm image circle, an APS-C lens requires a 28.4mm image circle, and a FF lens requires a 43.3mm circle. The APS-C circle is only 31.5% larger than a µ4/3 circle, while a full frame circle is twice (100% larger) the diameter of the µ4/3 sensor diagonal.