Advice needed on place to live outside Brussels

In general as soon as you get out of the central communes then it gets safer and greener. After that if you look at the areas near foriegn language schools then it normally means lots of expats so expat friendly. You need to state things like prefered local language, type of property required (some areas are very short on apartments but have lots of houses to rent). Age of kids (cetrain areas have only schools for below 12 years old so they may have to commute if older). Budget for property along with number of bedrooms would also be good.
Closer does not always mean that public transport is easy for instance I live 5km from Zaventem but to get there I would have to go all the way into town and back out as the local transport does not go directly there.

I live in Laeken (Pagodes area). Laeken is divided into two parts. The part where the new EU school is located which in my opinion is not a safe area to be living in. Even though the two parts are not too far away from each other, the scenery is completely different on my side. There are two trams (7 and 3) and the station is called DE WAND. There is also Strombeek Bever which is a minute drive from where I live but it is Flemish. Extremely nice area. I wouldn't recommend Grimbergen as it is too far away. Another extremely nice area with lots of green. Again Flemish.
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I livfe in Wemmel. There are numerous De Lijn buses which go directly to Rogier at a fare of €2 9or it is in the MTB zone if you want to use a MOBIB). It is green, clean and you can use French as freely as Dutch. It has decent shops and a Sunday market, more extensive shopping is available nearby at Jette and De Wand. Also close by in Jette are the top class UZ and Brugmann hospitals, and good French schools. By far the friendliest (ond most attractive) town hall of the five communes I have lived in. Significantly cheaper than the typical expat communes.

You mentioned Jette and Ganshoren. Jette is incredibly green but be picky about which area - it is a big place and you might find yourself a long way from the green spaces. Ganshoren - pretty much just suburbia. Neither brilliant for public transport - check the bus map.

2, 3 & 4 are easy.
So is safe.
However the "Welcoming" bit is difficult.
- How long do you expect to be here for?
- What are your language skills like?
- Where do you come from?
- Have you got family, and are they coming too?
- What sort of "expat" lifestyle are you expecting?

Understanding a bit about what sort of lifestyle you expect would help suggest places where you might want to live and what to look out for.

Single parent, good local schools, good facilities, urban but fairly green, easy & quick public transport to Rogier?
Look along the line 1 Metro line between Josephine Charlotte and Stockel.
It's not the cheapest area of Brussels, but you have a decent budget, and there's plenty to choose from.
You can also save on a car by using the Cambio car share system.

Aha I did suspect you only met Brussels city centre, so you WOULD consider Uccle and WSP. WSL, Watermael-Boitsfort, Jette, Koekelberg, Ganshoren, Berchem-Ste-Agathe, Laeken, which are all in Brussels?

2 bedroom apartment within those above areas within Brussels 1000 euro will be in budget even in more expensive areas. Be aware charges vary not just in price but in what is included and excluded. Eastern and southern communes have more rentals than western communes.

If it's just a "nice" place to live, so many! I live along metro line 1, probably pay 100 euro more per month but I pay it because the kids get many opportunities from living in that area.

Glen Brussels is a very green Capitol City even if you live in town. Be aware traffic into and out of town is horrendous in the peak times, pollution can be high near busy rods. The local trains are a good a reliable way in as is the metro. Local schooling is good but decent schools fill fast, however it's very exams orientated so if that's going to be an issue for your child, you need to be really sure they can pass, "failing" children have to double a year I have friends whose children did both Dutch or French local schooling both are similar in the exam focus from what I heard. In all cases parents being able to speak and write the language seemed to help the children pass the school system. It's not like British schooling. Do Investigate schools before you decide where to settle. Plenty of xpats in many communes. English language schooling is expensive because the schools get no tax breaks. The European schools are over subscribed and only really for families of those working for commission council etc. find a local sport that your child likes and join the local team to help with their language skills.
Some of the Flemish communes like Hoeilaart are nice good centre lots of parks and nature close by two train stations. Tervuren has a tram but it's slow into town because of all the stops and lots of expats there due to British school. I believe la hulpe is nice and has a train also, and this is near to Overijse Maleizen end of town at least.
Depends also if you want apartment living or house living that makes a difference. Not sure where you're based but suggest you visit if you can hire a car if possible and drive to the communes. Get a sense of the centre of the villages. Hope tht helps