Q. 3. Can one keep desiccated animals at home? If not, why are children’s dolls or the lions on the Aron Hakodesh permitted?

A. See above two questions. Poskim are even more lenient when the figures are made for children to play with them, since it is obvious that they are not being given any honor or reverence, they are just used as toys. (Maharit Y.D. 35, Peri Hasade quoted in Binyan Av 37, et. al., see Sh.Sh.K. 16: 108 in regards to making a snowman).
Poskim disagree about the propriety of decorating the aron hakodesh with sculptured or embroidered forms of lions. The ancient tradition of many shuln is to have a three dimensional form of lions either sculptured in relief or intaglio on the aron or embroidered on the poroiches, albeit only half of it. (Mordechai – Avoda Zara 3, 840, quoting Rabenu Efraim, Beis Yosef , Shulchan Aruch Y.D. 141: 4-5 ). Remoh (ibid.) maintains that when placed in a site where many attend, there is less reason for suspicion of worship.
Others consider this improper, especially in a place dedicated to honor Hashem. They mention that it is also a source of distraction (Avkas Ruchal 63, Rabenu Eliakim ibid. Sdei Tzoifim – Baba Basra 25b).
Horav Shlomo Miller’s Shlit’a opinion is to be lenient on children’s toys or lions on the aron hakodesh.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a