As mentioned on a previous thread, it isnt clear that te Remah (and presumably the MB who is commenitng on on him, is analagous ot our case.
The Rema is quoting an Ohr Zarua. the case there is where the Tzibur got together on shabbos but didnt lain. This is not our situation. Assuming Krias Hatorah is a chov on the Tzibur which I beleive is the common view) Thus even if a Tzibbur who got together, (thereby having a chiyuv but not fulfilling it) , that they have to make it up, We who’s tzibur sadly did not get together therby never was a chiyuv we MAY not have a chiyuv to make up even according to those there who require it.
“By that time we’ll be off from Israel beacuse the second day of Shavuos, they’ll be laining NAso in Israel,”
Why wouldnt they lain Bamidbar? (assuming they arent making up all the parshiyos or if they follow shitah that dont combine Seforim) What reason is there NOT to lain (just) Bamidbar. then they can be in sync with Chutz laaretz combining chukas and Balak and still fulfill Devarim before Tisha Baav. They gain an “extra ” PArsah – Bamdibar , with no down side (that I can see) other than it being a tad confusing