Building a Mega Froslass VGC Team Without Hisuian Arcanine

Yes

I don't have glimmora rn

Start with what you do have. We can make you the best team in the world but it doesn't matter if you don't have the mons

These are the pokemon I have access to.

My personal opinion is stick with what works with Harc, however that isn't what you are really asking for.

I would probably start with something like this:
M-Froslass
Incineroar (or Sneasler)
M-Garchomp Z
Kingambit
Volcarona (if no Incineroar) or Gholdengo
Indeedee (if using Sneasler) or Rillaboom

The original team was something like this (I adjusted it for BO1 shenanigans)

If you are trying to make something substantially different than my suggestion or your existing team, unfortunately idk if I can help with that. I picked them because they work well together. Judging by what you were running, I was right

You don't have a crazy amount of mons to work with and, even if you did, I don't think it would matter much. Froslass is finicky and requires a pretty specific team composition to work right

I think the team could work without Harc, but I don't think it would work nearly as well. If you made adjustments, I would try my suggestion out. I think it is definitely weaker to rain than what you currently have, but losing Harc means you have to make sacrifices elsewhere, and Yaichu is probably the weak link

Golisopod rain has been a big pain for me actually. What do you think of zard-y + froslass team. And adding rock slide on sneasler.

Personally, if I was going to combat golisopod rain, I wouldn't entertain yard at all. It is way too telegraphed. If you don't eliminate the rain threat, you will never have a chance of getting a KO off. Having your sun setter also be your attacker is much more difficult to pull off. Usually, I run a sand or snow setter vs goli rain matchups as well as a single fire type. Having more than 1 mon that primarily wants the rain shut off to do damage is too risky to run vs that team.

Last season lycanrock was used for rock type pressure.
But with the decline of chardy the need for it decreased too.

The trio of froslass - sneasler - kingambit is still very good.
Completing the team with whimsicott, volcarona, and hydreigon has yielded good results.
But you could also try to replace hydreigon with garchomp Z, or mega salamence. Or try gholdengo instead of kingambit. Or put in a rillaboom to get rid of psy terrain. Or incorporate froslass into a perish trap team with politoad, gengar, archaludon, rillaboom, and incineroar. Or you try out milotic in the team. Or you try a dual weather team with tyranitar+escadrill as a second mode.

Baseline: less chardy -> less need for rock

And if you still want rock, you can put rockslide on sneasler

Basculegion and raichu are also common options to have on the team with froslass

Don't stick froslass on perish

So how does froslass, gholdengo, sneasler, garchomp Z, volcarona and whimsicott/Indeedee/farigiraf sound.

I don't think farig and indeedee belong together tbh. They overlap WAY too much

And whims is not a bad mon but it isn't doing much in the current meta with psychic terrain being so prevalent. Like yeah you get tailwind and a good moonblast but that is where it ends

I personally prefer indeedee right now over farig until we get throat spray. Plus indeedee doesn't have to be on the field to keep priority off the table

The main problem is garchomp Z is floating, so priority is still a problem for it.

That is also true but seeds are very useful as a secondary effect of having indeedee

Top 7 at frankfurt, as mega glimmora as the rock type

I don't have glimmora unfortunately.

I still think froslass+indeedee+sneasler+kingambit is good. The trio is proven and indeedee protects against sucker punch, helps the sneasler, and helps against opposing terrain.
Last two Pokémon could make up an alternative mode like sand mode with tyranitar and escadrill, or sun mode with char-Y and venusaur, or rain mode with peliper and archaludon/golisopod/blastoise/swampert..., or a psy spam mode making use of the already included indeedee, or just a strong&fast mega like floette/raichu-Y/garchomp-z