You could use any yarn weight for these bunnies as long as you choose a fitting hook, it will only influence the finished size. My example rabbits made with DK yarn and 3mm hook are about 5” long and a little over 4” tall (without the ears).
The pattern is 9 pages long with many photographs illustrating the process. It is written in English with US crochet terms. Stitches and techniques used:
start with magic ring, chain, slip stitch, single crochet, single crochet increase, invisible decrease
Only the simplest stitches are used in the pattern, but a short row technique makes this an advanced level amigurumi (it is quite simple actually, but might be fiddly so it’s better if you have a safe grip on basics).
Finished items made from this pattern are yours to keep or gift away or sell, I only ask you to give me credit as designer in case you decide to sell them.