Plaster Q2 walls with roll plaster or other recommendation?

Yes, that's right, interior plaster comes quite early, so you might just wait until it arrives and then decide after assessing...

First of all, Q2 is already skimmed.

He is talking about filling, not plastering.

Roll plaster/paintable plaster usually looks d…… and can be used for the utility basement.

A clean filling is also required there because hardly anything is concealed with it.

And if you "only" want to paint, the preparatory work "filling and sanding till the doctor comes" is all the more demanding and not for "beginners".

The performance specification says nothing. I would have to ask the developer at the next opportunity.

We are looking for a fairly simple solution. What do you think about a surface sander to smooth the walls?

What kind of paints would you recommend for a KFW 55 house, regular ones or should it be lime or clay paints??

Roll plaster/brush plaster usually looks sh……y and can be used for the utility basement.

It only looks sh…..y if you make it so.
I don't understand how brush plaster can generally be downgraded to basement paint; imagination is never a bad thing when it comes to interior design.
Above all, it is often overlooked that it depends on what result the original poster wants to achieve; in that sense, everything can be wrong/right.

Is roll and trowel plaster the same?

I would like to have a uniform result on the walls as simple as possible. Light grain or texture is not a problem as long as it is even.

We have not plastered or sanded walls before, so I am looking for simple DIY options for a decent result.

A floor sander for an easy and even sanding would be an advantage, right? So you can sand large areas directly.

I would like to have a uniform result on the walls as simple as possible Light grain or texture is no problem as long as it is even

With good roll-on plaster you can't go wrong (e.g. Haering Deko Quarz Elf in fine - medium and coarse better camouflage small unevennesses in the substrate). You can also tint it, for example, and then you don't need a coat of paint anymore.

is roll-on and brush plaster the same?

Often yes. Everything is a fine plaster as a surface. You can often paint or roll it, depending on the desired result. However, I find painting, yes let's say "an acquired taste."