My Jones surname tree-climbing has presented all types of branches to explore. In the Kentucky and Virginia adventures, during family searches, you would find ancestors with the same first named followed by the letters "Sr." or "Jr.". My American upbring would explain that "Sr." occurring with another with the same first name, but followed as "Jr.", would mean that the "Sr." was the father of the "Jr." This finding would allow the connecting of these two folks correctly in your family tree. This phenomena would help many times fill in the branches, especially during the pre-1800s in Virginia.
Now crossing the great pond to England and, then to Wales, took me way back to pre-1200s. [the time that this blog presently reaches]! For many years the word "fychan" was assumed to mean "Jr." If the Welsh name followed another with same name, only accompanied by "fychan", it would mean father and son in the direct line to one another.
At this point in my Jones surname family tree, Irowerth fychan (JI-1) is followed by Gruffydd (JJ-1) and, then by another fellow name Irowerth (JK-1). All three individuals are labeled as being of Llwyn-Onn [now being discussed] and, given in direct line " father to son " in my family tree. Hum...let's see.
In my Blue Guide Wales, published 1990, V. Eirwen and Gwerfyl Moss discuss "The Welsh Language", pp. 59-65, stating that Fychan is a mutation of Bychan, and means small (p. 63) Whoa...mutation of words. What in the world does this mean? [discussed on page 60] Anyway, in my Welcome to Welsh book tagged "A new complete Welsh course for beginners", published 1984, by Heini Gruffudd, p. 130, states, "bach-small". In addition, my Welsh genealogical Research book by Charles M. Franklin, published 1995, gives the word "bach" to mean small (p.23) and the word "fychan" to mean younger (p.25). Finally, my The Shell Guide to Wales by Wynford Vaughan-Thomas and Alun Llewellyn, published 1969 (my early tree climbing days) gives "Bach (fem. fach). Small. ", whew...certainly not used to mean senior and junior, as used on this side of the great pond.
Small or younger, your guess is as good as mine when occurs the word FYCHAN.
P.S. My research is found in RN#6 titled Welsh Language.