I used to slash a while ago, thought about maybe doing it again.

Would it be difficult to find gear now that a lot of people have quit?

I was thinking either a caster character or something.

These days what is the preferred/most efficient feeder-pally setup? I don't think I ever made it past pally before in a season.

Should I go melee or cast and what kinds of charms/weapons do you recommend for what you're suggesting? I could get 50-100k+ FG for gear if I decided to slash again.

There's always gear available, depending on how much you're willing to spend. If you're looking for top of line equipment though, expect to be bumping threads for many months.

Swords and Strength gear can get you through paladin, but beyond that you'll need staves and dex gear and/or caster gear to progress further.

Interesting. Thank you for your input.

I like to play multi so I have people to interact with. However, if things in slasher are kind of dead is it important I be able to solo climb? If so what character(s) are best for that?

The weapons you have on this char are just about good enough to get you to solo through to MQ
https://forums.d2jsp.org/user.php?c=3&i=140286&p=173572
although there's a big gap between 35 and 55. This would involve playing as a barb, i'd recommend hitting at least 100 vita then rest of the points into strength (just in case you upgrade to a club/sword) these are also usable by paladin
There's also a decent amount of armors here, the 45 dex lvl 40 in particular will be very good for you.
Some decent charms here: https://forums.d2jsp.org/user.php?c=3&i=140286&p=211117 the level 15 with 29 and 25 with 37 strength are both very good.

You also have rogue daggers here:
https://forums.d2jsp.org/user.php?c=3&i=140286&p=210296
This would also work for samurai/monk/ninja. Other than a 32 dex robe here: https://forums.d2jsp.org/user.php?c=3&i=140286&p=289697 you're missing armors for rogue so i'd highly recommend choosing the barb.

So you already have the gear needed.
Just get on and play, good luck!
In terms of group play, random groups between level 5-80 occasionally form which you are free to join.
The main level 1-MQ groups i've written a guide about here: https://forums.d2jsp.org/topic.php?t=82759999&f=74
Although these arn't really happening at the moment.

Hmm. Didn't realize I even had any reasonable gear left. Long ago people approached me to buy off my staves and daggers and swords and axes and charms.

Thank you. I wanna go fast though as I get bored easily and have minimal time for playing. What would you suggest if you were starting from scratch?

as i mentioned. barb, stat vitality until you reach 100 vitality. then rest of stats into strength.
use the axes, armors and charms on them mules i mentioned.
ability wise, retribution/power strike to hit single targets for big damage are the most useful for now