Yeah, newb, whatever, you ask a good question like this and you tend to get good answers on here. Welcome to the Hide! It's unique here, that's a fact. We only run off the juvenile or mall warrior types or the type that ask for "strange" advice.
Now to topic:
All of these guys have great and solid advice. No take apart, not needed for rifle --in fact, Liberty stopped making some of their cans take apart because cleaning them and reassembly somehow caused the baffles to get out of alignment and caused lots of baffle strikes. Really shouldn't be using aluminum in suppressors at all these days, except in narrow conditions. No diffuser, just the blast baffle (and if you swing making that out of Inconel, that'd be ideal). That shit won't wear easy, and it'll make the can last a lot longer if you use one. The rest of the parts, 316 stainless is tough as shit AND fairly light considering. An Inconel/316 setup is what AAC uses, and despite their shitty mount, the can itself is really well made and sounds good too. No Inconel, no problem, just use 316 throughout. And you may be able to use titanium as the tube, since it sounds like you wanna save weight. But I don't know how you go about welding that to steel.
As for what type of baffle to use, well, whatever you use, use 316. I reckon other guys on here are more up to speed on what baffle geometry is best.
I know if I had my shop setup, this is what I'd be doing. As for welding, well, I know nearly nothing about that, other than a circumferential welding process is desired? So perhaps you may have to farm that out. I don't know, I likely would have to.
How did you other guys weld your cans together?
Good luck, and watch that run out when checking threads or threading a barrel, and/or when threading the can itself.