4 of the 8 schools I listed above are in Etterbeek.
I suspect your opinions of areas have been formed from hearing other British citizen's opinions of communes. Ixelles has the highest number of GBRs of any of the 19 Brussels communes. However it also has a disproportionate number of singles and couples who are GBR not families.
I take it you are after a very urban area with little green but lots of cafes? That is what Ixelles (north) is. Unfortunately it also mean fewer choices of after school activities, huge overpopulation means fierce fights for certain schools in the area.
Where is work exactly by street name?
Tell me what your priorities are? Remember all areas have shops, cafes, playgrounds (less of course in Ixelles), good public transport (but in Ixelles tricky to get to the EU quarter), so you'll get these things everywhere.
Absolutely make getting 2 school places a priority. If you really want very urban, I'd be going for Ecole du Bonheur as number one choice with a proven record of taking children aged 6 and 9 with no French where the head is happy to talk in English to newcomers and the school receives extra funding for non francophones with a student body of 30+ nationalities and no one nationality dominating other than Belgian and no other dominant language in large numbers (like Arabic or Turkish) which could make it harder for non francophones to be immersed into French.
The area between Montgomery roundabout, Merode metro and Square Plasky is pretty great and would give you urban vibes like north Ixelles but more for children. It's where du Bonheur is. Some of this area is 1040 Etterbeek, some is 1000 Ville de Bruxelles, some is 1030 Schaerbeek, some is 1200 Woluwe-St-Lambert or WSL for short. Even south of Merode metro down to la Chasse in Etterbeek is good. It's were la Farondole, La Colombe de la Paix, Ste Anne and St Stanislas are.
Other more suburban places which would suit new arrivals and give a huge choice of after school activities in French and English is WSP any area, WSL east to WSP is suburban (west is urban and where du Bonheur is situated. The most popular area is Stockel, it's maily in WSP but some of it is in Wezembeek and Kraainem. Really anywhere alone metro line 1 to Montgomery and tram lines 39 and 44 to Montgomery, it's all good and much more chance of school places here.