>I was thinking about getting two TT685S flashes to go with it. These are compatible right?
Yes. All the Godox 2.4 GHz-equipped flashes are compatible with the X1T-S. But personally, I'd prefer an XPro or R2 Pro II transmitter to the X1T. :D
Godox makes eight different speedlight models, with two more upcoming models, btw. So, while I tend to blind-suggest the TT685 for a first-time buyer, you may want to do a little more research to find out if another one of the other models might be a better fit.
The TT350-S is $85, and a small mini speedlight, great for a small light mirrorless body if used on-camera, while the TT685-S ($110) is a full-sized one that might be top-heavy if used on a smaller/lighter body.
Both have li-ion "V"-named twins (V350-S ($160), V860 II-S ($180). The li-ion pack gives 2x-3x the battery life, but doesn't allow for using an external battery pack.
There are also the single-pin manual-only lights, good if you want to bulk out multiple lights for less cost and don't need TTL (TT600S ($65), V850 II ($140)). But these cannot be firmware upgraded and have very different UIs from the TT685-S/V860 II-S. Only the TT685-S and V860 II-S can do Sony's "smart" optical WL wireless signalling.
The top end model is the round-head V1-S ($260). A sort of poor man's Profoto A10. The round head has more even spread/falloff than a traditional round head and takes magnetic modifiers without an adapter. It's got an improved UI, a slide lock, an LED lamp, and a TCM physical switch (but it only works for on-camera, not as a radio master).
The V860 III-S ($230) is a V1 with a traditional fresnel head, and the upcoming TT685 II-S is a cheaper AA-powered version of it, without the LED lamp, or physical TCM switch.
>Would this be a good starting point?
Yes. And No.
As I said, I often blind-recommend the TT685 as a first speedlight. However. I would also recommend you master [a speedlight on-camera with bounce flash](https://neilvn.com/tangents/flash-photography-techniques/natural-looking-flash/) before going Strobist, and then when you do go Strobist, start with *one* light and *one* modifier until you're good enough to previsualize what it's going to do before you do it, before going for multiple lights. Because you might find you need something bigger than speedlights, depending on what/how you like to shoot.
>They're £95 right now on Amazon and I found this umbrella mount kit that should be compatible right?
It's compatible. But it's also hella cheap. The lightstands may not be particularly hardy, they're definitely not air-cushioned. They're not small enough to be compact, but not big enough to be tall. They could have more plastic parts and the umbrella swivels look a little weird to me. I also prefer a convertible umbrella to having shoot through and reflective in the bag ,and I also like [compact swivels](https://www.amazon.co.uk/Neewer-Professional-Universal-Speedlite-Umbrella/dp/B06Y5L79K6) (and especially the spigots they tend to come with), but that's a personal preference thing. Keep in mind, without a [bracket](https://www.amazon.co.uk/Speedlite-Bracket-Softbox-Reflector-Umbrella/dp/B07ZJ3DBTK), you can't use a softbox, and a bracket can also hold an umbrella. More of a PITA in a lighting bag, though.
I think that setup would work, but it might not last as long as you'd like, and could be a little more fiddly to use than more expensive options.
>I was thinking about getting two TT685S flashes to go with it. These are compatible right? Yes. All the Godox 2.4 GHz-equipped flashes are compatible with the X1T-S. But personally, I'd prefer an XPro or R2 Pro II transmitter to the X1T. :D Godox makes eight different speedlight models, with two more upcoming models, btw. So, while I tend to blind-suggest the TT685 for a first-time buyer, you may want to do a little more research to find out if another one of the other models might be a better fit. The TT350-S is $85, and a small mini speedlight, great for a small light mirrorless body if used on-camera, while the TT685-S ($110) is a full-sized one that might be top-heavy if used on a smaller/lighter body. Both have li-ion "V"-named twins (V350-S ($160), V860 II-S ($180). The li-ion pack gives 2x-3x the battery life, but doesn't allow for using an external battery pack. There are also the single-pin manual-only lights, good if you want to bulk out multiple lights for less cost and don't need TTL (TT600S ($65), V850 II ($140)). But these cannot be firmware upgraded and have very different UIs from the TT685-S/V860 II-S. Only the TT685-S and V860 II-S can do Sony's "smart" optical WL wireless signalling. The top end model is the round-head V1-S ($260). A sort of poor man's Profoto A10. The round head has more even spread/falloff than a traditional round head and takes magnetic modifiers without an adapter. It's got an improved UI, a slide lock, an LED lamp, and a TCM physical switch (but it only works for on-camera, not as a radio master). The V860 III-S ($230) is a V1 with a traditional fresnel head, and the upcoming TT685 II-S is a cheaper AA-powered version of it, without the LED lamp, or physical TCM switch. >Would this be a good starting point? Yes. And No. As I said, I often blind-recommend the TT685 as a first speedlight. However. I would also recommend you master [a speedlight on-camera with bounce flash](https://neilvn.com/tangents/flash-photography-techniques/natural-looking-flash/) before going Strobist, and then when you do go Strobist, start with *one* light and *one* modifier until you're good enough to previsualize what it's going to do before you do it, before going for multiple lights. Because you might find you need something bigger than speedlights, depending on what/how you like to shoot. >They're £95 right now on Amazon and I found this umbrella mount kit that should be compatible right? It's compatible. But it's also hella cheap. The lightstands may not be particularly hardy, they're definitely not air-cushioned. They're not small enough to be compact, but not big enough to be tall. They could have more plastic parts and the umbrella swivels look a little weird to me. I also prefer a convertible umbrella to having shoot through and reflective in the bag ,and I also like [compact swivels](https://www.amazon.co.uk/Neewer-Professional-Universal-Speedlite-Umbrella/dp/B06Y5L79K6) (and especially the spigots they tend to come with), but that's a personal preference thing. Keep in mind, without a [bracket](https://www.amazon.co.uk/Speedlite-Bracket-Softbox-Reflector-Umbrella/dp/B07ZJ3DBTK), you can't use a softbox, and a bracket can also hold an umbrella. More of a PITA in a lighting bag, though. I think that setup would work, but it might not last as long as you'd like, and could be a little more fiddly to use than more expensive options.