Heya,
Have you considered brolly boxes? They're umbrella based soft boxes, so a reflective interior surface, with a softbox cover that velcros onto the surface. It's an umbrella at heart, so it opens up like one and transports like one. They're inexpensive and really give you better control over spill and have less of a hot spot compared to a shoot through umbrella. They don't cost much different either. I use them with strobes & speedlites, they're a "do all" modifier to me. Look for Godox or Neewer (smae thing) 47" brolly boxes, they're inexpensive and pretty good. I use my brolly boxes over my much more expensive EZ-Pro 48" Octa even (lighter weight, easier to use, easier to transport around, same good light).
Another good modifier to consider is a Photek Softlighter II, any size you wish, larger is more appropriate for a strobe, but indoors, a speedlite can still be used with it. Very nice soft light.
Also know that you can always double up and gang up your speedlites to get more out of them in large modifiers to get more spread, more output, etc.
As for stands, I would get a fairly sturdy boom stand. It's worth it in the long run. One thing I've never regretted in buying is a sturdy mount. Just remember it only stings once to buy it, so spend early on a good stand, and it's a good stand for all your lights. Don't go cheap on a stand holding expensive lights and modifiers.
Very best,