How do I add more roster spots?

I’m pretty sure I found my answer, but just wanted to confirm. I made a trade where I gave up 2 players and got back 5 players. I thought since I was putting 4 guys on the IL, that I would have the roster spots without cutting people (yet) - i knew cuts would have to be made as guys came off the IL. But I noticed my team still said 40 out of 40 even after putting guys on IL. Re-reading the rules, I think I now understand that someone needs to be on the 60 day IL to get those roster spots not to count. So now I will have to cut a bunch of people. I got this correct now?

I think this question is more about IL spots on the lineup. They do not give you extra roster spots. Extra roster spots only come from players who have 60IL, SUSP, COVID-19, or OPTOUT statuses with MLB.

Let’s bring the trade element into it. Can I trade a player(s) for strictly a loan (cash) and not get a player back in return?

Yeah, absolutely. You can trade a player for nothing, including no loan if you want. Of course you’re gonna want to do this transparently and get a few other teams in your league involved.