I have 2 brands in the same market. I want to create authority blogs. Same content would work well for both. What is the best way to approach this?

TL;DR -> Yes you will risk it if you don't perform a proper audit and migration from the original platform. Any type of architecture changes can 100% ruin your SEO if you are not migrating content and topics correctly. Many people assume this is limited to URI structure but underestimate the power of Topical hierarchy and the content, internal linking and URI structure which play a crucial role into any migration effort. If you have any questions about the migration process, give me a shout. Decent free migration checklist: https://searchengineland.com/site-migration-seo-checklist-dont-lose-traffic-286880

Two key concerns are 1. Customer confusion with the 2 offerings: Imagine being in an art gallery that sells photography training and fine art or a book store that tries to sell you fine art. Even if it's the same group of people, they may be in very different mind-sets and hence may not associate both together. 2. SEO challenges with mixed messages you're sending. Which keywords would you optimize for which part of the site? Advantage would be if the customer base is the same group of people, hence offering cross-sell opportunities. For instance, if your MAIN source of leads for the training site is the art site, then this would be more important. In general, I would suggest one site for one customer group. If there is likely to be a very high overlap, then same site, with multiple sub-sites might work. In matter of fact, it'll probably be EASIER to do two sites for this than one site. Your designer will thank you :) Then tastefully add cross-links in the places where someone is likely to use them. For instance the art gallery could have a post 'How I make art' and links to your other business there. And the photog training site would have your art pics with subtle on-image links to your art biz. While I'm not a branding expert, I do find that my engineering lead approach to challenges in Marketing/Sales usually works, and provides clarity and direction.

Typically just moving from one server to the next has no issues at all so long as you're not making any other changes to the site, such as changing URLs in a re-design process. Just make sure its a quality, respected server. If the server has issues then, yeah, you'll inherit them. But otherwise you'll be fine.

The cost of SEO depends a great deal on three things: 1) The specific services being offered (SEO, social media, content strategy, etc.) 2) The degree in which those services will be implemented (how many hours per month) 3) the skill and experience level of the SEOs involved. $800/month is a pretty small investment if you consider all the layers to making a web marketing campaign successful. My company will usually not touch any fully-managed web marketing campaign for less than $1500/month and that's at the low end of the aggressiveness meter even for a pretty basic site. A larger ecommerce site might start around $5K and go up from there. Overall, you want to look for value and results. You'll want to know how long the SEO has been in business and when looking at proposals you need to understand the amount of time the company will be investing in the campaign. You also want to spell out your goals and establish the expectations on how/when those goals will be achieved. When the SEO and client don't have the same expectations, that can lead to issues later on. But if you know what the goals are you can both be on the same page from the start.

If you got 5000 sites to link to your site using the same keyword you'll likely be flagged for spam and attempting to manipulate the search results. That is an old-school attempt at SEOing a site that Google and the other search engines have already developed algorithmic answers to. There are three aspects to building up your search rankings. 1) On-Site Optimization: Your site has to be coded in a way that is search and mobile friendly. You need to optimize your content for searcher's topical interest's (keywords), and give your visitors a great on-site experience by focusing on usability issues. 2) Content: You need to create and publish awesome content that fills the needs of the audience you're trying to reach. Write blog posts and create other forms of content that answer questions, provide tips, and map out solutions that truly illustrate that you are an authority on the topic. 3) Social Engagement / Links: Links are an important part of the algorithm, but getting a bunch of sites to link to you using keywords is the wrong approach. You need to be engaging on social media and (to a far lesser extent) socializing your content above. But the more you engage, the more others will socialize your content for you, which is where authority is really built.