Soldiers similar to Slujitori Armasiei in action in 15th century. though the image comes from the 16th century, so there was likely some contemporary influence. Though the image is rudimentary (and blurry, sorry about that) you can notice the breast-plate, helmet style (guys in the middle) and the halberds and boots.
Steel breastplate covers the torso. Arms are covered up to the elbow either by leather lamellar armor or chainmail. The rest of the arm is covered by a loose-fitting cotton shirt. Chainmail extends halfway down the thighs for further protection, covering the long shirt.
Follow the image above as a good guide for the entire unit.
Similar to the upgraded viteji, composed of a more oriental style (Russian) helmet with chainmail underneath that extends over the shoulders and the front and back of the torso. The coloring is steel. Helmet could also be similar to one already used by the voinic unit.
Leather boots extending halfway up the shins. The legs also have metal knee protectors. Long cotton pants are worn, coloring usually light or tan.
Primary weapon is halberd, but can switch to straight-edged longsword as secondary weapon. No fancy decorations on weapons.
Tan, short leather gloves.
Steel breastplate still covers the chest, but in addition laminated steel armor covers the upper arms, thighs, as well as steel greaves covering the shins. Round steel plates cover the front of the armpits. A long-sleve chainmail shirt is worn under this. The steel plates could have a small spike on them or not, and could also vary in design. Look at pictures for inspiration, I think samples exist in M2:TW on the Gothic knights, so you don't need to make them from scratch.
^The above image is a good design to follow.
A laminated steel plate, curving around 1/3 of the leg's circumferance, covers the outside of each thigh, and in addition, steel greaves are worn. Same boots as before.
^Example of thigh protectors attached to the cuirass.
^ Shape of greaves, note how it's not supposed to be form-fitting.
^ horizontal lamination pattern used on thigh protectors.
Same as Ottoman voynuk infantry.
Same as before.
This unit is supposed to be a rare, elite unit, symbolizing the advancement of arms in Wallachia at the end of the 15th century, and beginning of the 16th century (in upgraded version).