Do rawm and ishmam apply to idgham al-kabeer when reading al-Susi, while making the first letter sakin, both when pausing and continuing?

It is permissible to perform Ramm (partial vowelization) and Ishmam (lip-rounding) on letters other than Baa’ (ب) and Meem (م) if the letter has a ḍammah (ḍamūm). Ramm is also permissible for letters with a kasrah (maksūr), but Ishmam is not permissible for letters with a kasrah. Neither is permissible for letters with a fatḥah (maftūḥ). Al-Shatibi stated: "And perform Ishmam and Ramm on other than Baa’ and its Meem, or with Baa’ or Meem, and be observant." Abu Shamah explained this by saying that Ishmam and Ramm are permissible in all letters that are assimilated (mudghamah) in mutamāthilayn (identical letters) and mutaqāribayn (close letters), except in four cases: when Baa’ meets another Baa’, or a Meem; or when Meem meets another Meem, or a Baa’. Ishmam applies to letters with a ḍammah, and Ramm applies to letters with a ḍammah and a kasrah, and neither applies to letters with a fatḥah.