Hi Mark, Great questions!!
For the first question, yes you can definitely get photos and a walkthrough video from the seller to show the buyer. Or take them yourself! Another option is to hire a third party home inspection group that does this for you and takes the walk through videos and photos as well as documents any issues the inspector sees and sometimes provide quotes on what they think the repairs are. Thirdly, if the buyer is local, you can always meet them and have them check it out or like you mentioned have them go on their own! Typically, once you get established, a lot of big time buyers do not physically check out the properties anyways, it’s all done with photos and inspection reports.
For the second question, just make sure you have a really good purchase contract and a really good assignment contract! This can help with buyers trying to bypass you.
If you need help in this area let me know, my team and I do micro-lending aka transactional lending where we help wholesalers who do not have the funds for the earnest money deposits. This helps them take on more deals without tying up their own funds! We can help you with getting a good contract in place!