Ar Lan y Môr is one of those songs which has various verses, depending on personal preference. Also, even in the most-sung verses, the folk process creates minor variations. Your three are pretty much part of the standard 'kit'

Ar lan y môr mae rhosys chochion
Ar lan y môr mae lilis gwynion
Ar lan y môr mae 'nghariad inne
Yn cysgu'r nos a chodi'r bore.

Note: one 'd' in 'chodi'

Ar lan y môr mae carreg wastad
Lle bum yn siarad gair â'm cariad
Oddeutu hon fe dyf y lili
Ac ambell sbrigyn o rosmari.

I think this might be Max's version, although I think a lot of us sing "O amgylch hon mae teim yn tyfu" for the third line. Also note the correction in line 2 (â'm).

Llawn yw'r môr o swnd a chegryn
Llawn yw'r wy o wyn a melyn
Llawn yw'r coed o ddail a blode
Llawn o gariad merch wyf inne.

Again, I think a lot sing "Llawn iawn" at the beginning of each line here, and "llawn iawn o gariad ydwyf inne" for the last line. (But I'm working from memory.) There's an historical reason why I prefer doing this (as well as the argument for keeping the pattern of previous verses); one ethnomusicologist has suggested a connection between the several Welsh songs starting with a 4 or 5 single-note opening, with the old-time Welsh preaching 'hwyl'.

Another two verses which are commonly sung are:

Ar lan y môr mae cerrig gleision
Ar lan y môr mae blodau'r meibion,
Ar lan y môr mae pob rhinwedde,
Ar lan y môr mae 'nghariad inne.

Mor hardd yw'r haul yn codi'r bore,
Mor hardd yw enfys aml ei liwiau,
Mor hardd yw natur ym Mehefin
Ond harddach fyth yw wyneb Elin.

sian