Advice needed for building two PCs for the kids

[jonww74]

I've decided to get the kids (10&12yrs) thier own PC (each) since they keep on hogging the laptops/xbox.

I have spare bits as follows:

1. 1x MSI Tomahawk MAX AM4 motherboard.
2. 1x i7-920 CPU + motherboard + 12G RAM
3. Spare HDDs

They mainly play Roblox, Sims4, Minecraft at the moment but will probably move on to bigger (?) games at somepoint.

My plan is as follows, get an Ryzen AM4 CPU with iGPU (e.g. 3200G) plus ram for one.
And get a 1050Ti for the i7-920 setup.

The eldest likes to edit videos and make pics of her gaming so I reacon the AM4 system would be okay.
The youngest likes to play more varied games so I'm thinking the 1050Ti for him.

Questions I could do with opinions on:

1. Should I get a cheaper AM4 cpu and use another 1050?
2. Are 1050ti's still a good buy. I've seen them at ~£175 which is still a lot for these builds.
3. Are 1030s a better buy?
4. It maybe more cost effective to by a CPU bundles these days. Should I sell the Tomahawk and get one of those instead? Preferably an M-ATX one.
5. Obviously price is paramount, I was hoping that using my old bits would work out but the current chip shortage/price-hike isn't making this task fun.

Any thoughts appreciated.