Considering rescuing another hammy friend, have some questions

Just getting it out if the way that I absolutely do NOT mean housed together. They will never meet each other.

Now that that is out of the way, a little story- I found out there are actually a few hamsters near me that could use a new home! I have the space, and the means to do so, and would love to give more hamsters a better life. My current hamster is my everything, housed in two Nightangel cages put together, going to be three when the next one comes in. I was thinking I would put the 75 gallon tank to good use and rescue another hammy until I can order more Nightangel cages and spilcers again for him or her to move into as well to have even more floors pace than the 75.

My questions.......

*if they are in the same room, will they be able to smell each other and will that stress them out? I was going to keep the enclosures in the same room, but I can also not do that. Maybe paranoid but is there any risk of them somehow getting in each other's cages if in the same room? Or do you think they would be unaware of each other?

*Do you find it hard to give both adequate attention? I know they don't care about human interaction the same way, but I can't stop my brain from worrying one will be treated "unfairly" somehow- more affection, treats, playtime, etc.

*one of the hammies was a ww dwarf that they said was about 3. Isn't that super old and do you think the stress from moving would hurt him? I've also never had a dwarf, only syrians.

Thanks!