Re-enabling exports for Marwari (rwr)
Ok, so develop a bit further the incubator in that language (even if the UI itself is still not translated, you can add content there, to attract more people). Then together you'll register the users in the portal, and will together ask to translate the UI ; you'll start by the 700 core messages, if you're active enough, this will be loaded in Wikimedia Incubator for continuing your tests there with this UI in beta stage in Incubator.
The initial phase for these ~700 core messages is important: you'll probably have to change various messages multiple times to get a consensus and have a coherent UI. You may not need to translate all the 700 but at least a significant number (about 85% should be enough to allow them to exported from translatewiki.net and imported first in your Incubator wiki).
As consensus will progress, you may have these messages also used for other incubator projects (Wikipedia is not just the one you'll want to experiment, probably a Wiktionary edition will be useful to document your terminology, and some Wikisource for importing some important texts usable as a reference, such as local laws, or famous literature or religious texts).
You'll have to make sure that Marwari is not confused between the variant used in India and Pakistan, using different scripts. Note that these variants have different scripts, but both scripts may be used: one of them is just prefered in India, another (Perso-Arabic) prefered in Pakistan but they both exist in both countries.
Starting a new language is a long patient work. The initial steps are not easy and must not be negected: it's less important to have big statistics on tyhe number of messages translated than to have the base core functional, tested, vetted with other users that could help you find better alternatives you did not initially thought about. That's why it's important to develop a local community: The Wikimedia incubator can help you develop it and then demonstrate that it is active and that it interests more users. And the only way to interest more users is to start developing content in that language, for various topics of use (in my opinion, developing a dictionnary and starging trascripting some important cultural texts are the most important goal; don't waste too much efforts on creating a custom presentation and layout and many templates except some navigation boxes that will link the esssential content and will allow more users to find them and then start expanding them).