Solo Arcanine

I found this spreadsheet to be helpful in deciding which to choose for raids. But I think ultimately pokebattler is your best bet because it'll show you that starmie and omastar get wrecked vs Arcanine despite the higher DPS.

According to pokebattler the Crunch movesets are easiest. It's also the only moveset I've succeeded against, mainly because I haven't felt the need to try again after I beat it.

https://docs.google.com/spreadsheets/d/1sn9XiNlwAXxwccK-YtJo_vM6nZRN4VhGjm2cKhuaZBo/htmlview?sle=true#

Need more Golem and Rhydon!

The times I've done arcanine, I've used Golem and Vaporeon. If it had crunch, use SE Tyranitar. I don't think I've used more than 4 pokemon. Also, I haven't run across one with wild charge yet.

Fire blast is definitely easiest for all teams. I think 1, 2, 3, 6, 7, 8, should suffice for the solo? You might struggle with Wild Charge with that lineup though, so it's always great to have Golems ready (as a reference, with no dodging it takes around 5 Level 30 golems to beat)

I have soloed quite a few arcanine no matter the move set always start with golem with RT, SE either my 2600CP or 2300CP then utilize Vaporeon with hydro pump or aqua tail. I prefer choosing a Pokemon with a multi bar charge move to finish off the raid boss. I would advise against Pokemon that aren't dealing super effective quick and charge moves like Tyranitar and I would stay away from Rhydon because mud slap is a let down. Here is my tried and true team most of the time I only go through 4 or 5 Pokémon.
Golem 2300Cp RT/SE
Vaporeon 3070 hydro
Golem 2500 RT/SE
Golem 2800 RT/RB
Vaporeon 3080 aqua tail (Rarely used)
Dragonite 3500 dragon tail outrage (almost never used) I finish with anywhere between 5-20 seconds left.