Wordpress custom plugins

Hi. We want the best! We have a (service based) marketplace site and need 4 x custom Wordpress Plugins for checkout/payment: Our site (like FIverr) sells a service. It is only 1 product but with many people offering bids. The checkout will always be a single figure, but dynamic/changing. So 1 person will have a $500 checkout bill, next person may be $270, next may be $325 etc... We are not working a credit system. We want to create the following payment plugins: 1 - The easy & simple one!. We require a standard payment gateway (usual VISA Mastercard etc) there are many on the market, but we want a custom one (or a re-skinned one) so it is in-line (design/UX-wise) with the following: 2 - We want an installment payment method plugin (as in Layby/Lay-buy/Layaway) where there is a deposit and then periodic payments. This needs to enable the customer to decide how much to deposit (out of 20%min, 30% 40% or 50%), then work out how much per WEEK remains until the total price is paid off, across a 12 week period. This information, once populated, is then submitted to our payment provider will take the initial deposit payment and then sweep the other payments automatically. The CMS needs to allow us to change payment parameters at all times. 3 - A 'group-buy/donation/crowd-funded' plugin. We want our customers to be able to deposit their own funds as above into this plugin, but also invite friends and family via a link they can send (via social media-Facebook- and email) to help them purchase the product within a 6 week timeframe. Kind of like a gofundme model. Again there are many charity and crowd-fund themes available, but they don't do what we want! This will need to recognise the checkout price and then have a target thermometer or similar to show progress details. When somebody donates funds, it will need to send an email thank-you to the donator and also alert the customer and us, and show in the progress thermometer/graph. 4 - Buy now Pay later plugin. See Afterpay/Openpay/Oxipay. We want to offer the clients an option to pay 25% or 50% deposit and then 2 or 3 x 25% payments every 2 weeks following. Again submitted to our payment provider who will take the initial deposit payment and then sweep the other payments automatically. All of these plugins need to be very simplistic and look similar/on-brand and have a similar UX. All payments will go to the same bank account in the back-end but will each need separate CMS / reporting.